Out in the country-city mix known as Prince George's County, where townhouse developments have rural delivery mailboxes at the curb, stands a 450-acre park where kids can't decide what to do first.

The debate began as soon as we pulled into the parking lot of Watkins Regional Park, near Largo.Six-year-old Tabitha heard train whistles and wanted to go on the miniature train. Her friend Emily heard calliope-type music, which pulled her toward the carousel. Caroline, three, eyed a playground. She won, only because the train wasn't due to leave for another 15 minutes and every horse on the carousel already had a rider.

The playground, too, was fraught with the necessity to make decisions. Emily climbed to the top of the rocket slide, one of about a dozen slides of every possible size and shape. Tabitha and Caroline rushed to a do-it-yourself merry-go-round. Then they tried every single swing, rocking horse, and seesaw. Other families, too, seemed to be rushing around sampling everything.

"You're Cinderella, get in there," said a mother depositing a little girl in a facsimile of Cinderella's pumpkin coach.

"Hurry, I'm going in that yellow thing," yelled a boy to a family trailing behind.

"That yellow thing" was a tall metal structure with several slides twisting down from the top. Emily, Tabitha and Caroline never got near it. Not that they were scared or anything -- they just felt it was time to visit the nature center, a short walk down a muddy path.

The nature center had so many attractions that the kids spread out in all directions.

"Look, Mommy, turtles," said Caroline, discovering an indoor pond with fish, insects and turtles.

Emily opened a cupboard door, revealing a wolf spider behind glass and the information that wolf spiders have eight eyes -- four looking down, two looking up and two looking ahead. Tabitha cheated at a game whose object was to match leaves with trees. A barn owl looked down at us from his roomy cage. An albino skunk slept in another.

"He eats cat food," observed Caroline looking at a full bowl of something that looked like cat food.

There were microscopes to look through, herbs to smell, horns that sounded like geese. The only way I could pry the kids out of there was to mention the carousel.

The carousel was rescued from Chesapeake Beach, a resort long past its prime, by a local carousel buff named Orva Heissenbuttel. The carousel's last go-round in Chesapeake Beach was on Labor Day of 1972. Shortly thereafter, Heissenbuttel saw a classified ad offering the equipment for sale. Alarmed that the carousel might be dismembered and sold as folk art, Heissenbuttel waged a successful campaign to have the Maryland National Capital Park and Planning Commission buy it. Many of the hand-carved animals on the turn-of-the-century carousel have been restored with funds raised by Heissenbuttel.

Even the carousel required decision-making. Caroline was tempted by an ostrich, goat and a kangaroo, but finally settled on a buffalo. Tabitha chose a green seahorse. Emily climbed up on a classic horse. The animals went up and down and round and round for so long that by the time we got off we had missed another train.

Instead, we took a short walk to the Old Maryland Farm, home of goats, sheep, chickens, ducks, rabbits, pigs and vegetables. Unlike other Maryland parks we've visited, where the animals live in concentration-camp conditions, the Watkins farm has roomy pens in a wooded setting.

"He's ducking down," said Tabitha, watching a goat lean on the knees of his front legs to reach his food better.

Fern and Flo, the pigs in residence, were eating, too -- tomatoes and squash grown in the vegetable patches nearby.

"Are they all named Tom?" asked Emily of the inhabitants of a pen labeled "tom turkeys."

Nearby, four different kinds of rabbits, one of them with babies in a hair-lined nest, rested in separate cages.

"Why aren't they together? Do they fight?" asked Caroline, who knows what it's like to have a sister. Rather than explain I led the kids, through a light rain, back to the train station.

The little red train was in the station, but the young woman engineer announced it wouldn't be going out on its one-mile trip through the woods again.

"The tracks are wet and the train can slip off, and it won't go up hills," she explained to the disappointed kids.

"We'd probably have to get out and push it uphill," I added, knowing right away it was a mistake.

The kids' eyes lit up. "Yeah," squealed Tabitha to Emily excitedly. "We'd have to get out and push." GETTING TO THE PARK Watkins Regional Park is open daily. To get there, take Maryland Route 214, a continuation of East Capitol Street, past the Capital Centre to Enterprise Road (Route 556). Turn right onto Enterprise Road and follow signs to the park.

A $3.00 per car fee is charged on summer weekends. Rides and admission to the Old Maryland Farm are 50 cents each or three tickets for $1.25. The farm and the nature center are closed Mondays.

There'll be an elderberry hike this Saturday, a scavenger hunt on August 29 on which kids 8 to 15 will search for a list of natural objects to make into collages; and a campfire program August 31. For reservations and to find out about hay rides, hikes and other programs available to groups, call 249-6202.