DEAR ABBY: My recent vacation trip has compelled me to pass along some tips to those who visit our precious national parks -- particularly Yellowstone.

1. Don't bring your dog a1ong -- at least not to Yellowstone; pets are not allowed past one-quarter of a mile on any trail there. I couldn't believe all the dogs I saw locked in cars in 80-degree temperatures! Better check the pet regulations of the park you plan to visit before deciding to bring your dog. (Bears dislike dogs, so you'd be asking for trouble.)

2. Extinguish your camp fires when you leave your site.

3. If an animal wants to cross the road -- let it! You're only a visitor -- the animal lives there, so be polite. (I couldn't believe how many people I saw impatiently blowing their horns to force a buffalo or deer back to the side of the road.)

4. Those lovely wildflowers are not yours -- they belong to everyone; so please leave them there for the next person to admire. Leave the rocks and stones in place, too.

5. If you want a close-up shot of an animal, invest in a camera with a zoom lens. I actually saw 25 or 30 people bounding across a meadow, surrounding a giant elk and snapping away within 50 feet of the beast. (Do they think those animals are stuffed? If they ever get gored, they'll find out.)

6. Believe in signs. If you see a sign that says "Danger" or "Stay on Trail" -- believe it. Everyone acts like he's working for National Geographic. The best picture does not necessarily lie beyond the "No Farther" warning. You're better off settling for an OK shot than not living to see the shot of a lifetime. -- MARY WIESEMAN, INDIANAPOLIS

DEAR MARY: Thanks for the travel tips. Do you mind if I add a tip or two of my own?

1. Don't litter. Carry a folded bag in which to stash your trash.

2. Wear comfortable shoes, sunglasses and sunscreen, and a whistle on a flexible cord around your neck. Be sure your children are outfitted the same way.

3. Keep an eagle eye on your kids at all times.

4. And if you smoke, douse the butt with water to be sure it's out.

"How to Be Popular" is an excellent guide to becoming a better conversationalist and a more attractive person. To order, send a long, business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Popularity Booklet, P.O. Box 447, Mount Morris, Ill. 61054. (Postage is included.)

DEAR ABBY: I am the mother of a 7-month-old daughter, and another child is due in December. My husband and I were married last January and now we are being divorced. I'll be 21 in October, and I am terrified of being a single mother with two children, not to mention the fact that my husband has paid only $50 in child support. Clothes, food and diapers cost a lot of money.

Abby, this second child was a complete shock, and I'm not sure I really want it. I have no feelings for it. Am I making sense? I feel as though my world has no meaning except for my family, the child I have and myself. I don't know what to do.

I have dreams of how I could hurt myself badly enough to kill this child inside. I wish I wasn't pregnant, but I don't believe in abortion and I couldn't give it up for adoption.

Mom tells me I will have feelings for this baby when it begins to grow. Has anyone ever said this to you before? I will care for it, but I'm afraid that I will never love this baby. Scary, huh? What should I do? Help! -- SCARED IN WASHINGTON STATE

DEAR SCARED: If you are having dreams about how you can "hurt" yourself enough to be rid of the baby you say you may never love, cannot support, and did not want in the first place -- please talk with a professional counselor or a clergyperson about giving the child up. There are many couples waiting (and praying) for a child to adopt. They would love and provide for it in a way that you can�not. Please consider that option. You need not feel guilty for facing reality. I think you are sensible and courageous. I wish you well.

DEAR ABBY: I am a delivery driver for a major pizza restaurant in Atchison, Kan. I've seen all kinds of things while delivering pizza, but one thing I've seen often, worries me.

Many adults send their small children to answer the door and pay for the pizza. I've had children as young as 3 and 4 years old meet me at the door with no adult in sight. One woman sent her 5-�year-old son to the door, and when there was a problem with the order, he had to get her from a second-floor bedroom!

One little boy even let me in the house, saying that he was the only one at home. I love children myself and don't have a problem dealing with them, but people don't know me. How do they know I won't try to abduct their child, or do something terrible to him or her? We read about things like that happening to children every day!

Abby, please tell people that if they want to let their kids "pay" for the pizza, that's fine, but they should be within a few feet of the child when the child opens the door. It could prevent a terrible tragedy. -- A PIZZA DELIVERY DRIVER

DEAR DRIVER: Thanks for a valuable letter. You delivered something far more important than a pizza today.

What teen-agers need to know about sex, drugs, AIDS, and getting along with their peers and parents is now in Abby's updated, expanded booklet, "What Every Teen Should Know." To order, send a long, business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Teen Booklet, P.O. Box 447, Mount Morris, Ill. 61054. (Postage is included.)

DEAR ABBY: My problem is the 40-year-old husband of my 30-year-old daughter. He believes that because he is "family," he is entitled to come into my home and help himself to anything he wants in my fridge or cupboards. He has done this for several years, even after having been told (by me) that this is unacceptable. After complying for a while, he went back to helping himself to food and drink as though he were in his own home.

His manners are atrocious. He doesn't wait to be offered a second helping -- he takes what he wants, sometimes ignoring the serving utensils and using his fingers. He weighs 260 and is a big eater. He complains if I don't have his favorite beer, suggesting that I buy it by the case so I won't run out!

My daughter caters to him, asking him (in my home) if he wants more of anything.

Because of the distance they have to travel to visit us, they always spend the night. My husband and I always give them our bed�room. When we spent the night at their place, we slept on a broken�-down sofa that they brought in from the toolshed.

I know there is very little you can do to help me, Abby, but I need to know if being "family" is a legitimate reason for my son-in-law's behavior. -- APPALLED IN CANADA

DEAR APPALLED: Being "family" in a family of pigs might excuse this inconsiderate oaf, but in a family of reasonably well-bred people, his behavior is not acceptable.

DEAR ABBY: I handle "lost" property for a large hospital, and I see so much heartache, I feel compelled to write.

Abby, advise your readers to please leave all valuables at home, especially their precious wedding rings with stones and other "real" jewelry or religious medals.

I cannot tell you how many people I have seen who have been robbed of their jewelry and other valuables. The elderly are especially vulnerable, as they are sometimes confused. Their rings are often loose after years of wear and are easily slipped off by thieves.

A tip: Never tape a ring to a finger -- it's an advertisement to come and get it.

Even the dead are being robbed. If you arrive at the hospital unexpectedly, send your valuables home immediately with a friend. If you're alone, insist that the nurse (no one else) lock up your rings in the hospital safe. She will place them in a special "valuables" envelope and will give you a receipt.

Most hospitals are wide open to the public, and that includes thieves as well as fine and dedicated employees. Also, hospitals are not responsible for lost valuables. We cannot afford to reimburse patients for theft. Please sign this ... WORKING A NICE BAY AREA HOSPITAL

People are eating them up! For Abby's favorite recipes, send a long, business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Cookbooklet, P.O. Box 447, Mount Morris, Ill. 61054. (Postage is included.)