Picture this familiar vacation scene: The family car is rolling down an unfamiliar interstate at 65 mph when someone suddenly announces they have to go to the bathroom bad.

Is a rest area within reach? Does the next exit have services? Can you couple a stop there with lunch, knowing that fussy Sue will agree to eat in one restaurant chain only?The computer revolution hears you, and has a solution (one of the industry's favorite words).

Software is available for your home computer that can plan your summer vacation trip down to the minute, to the penny, to the exact brand of gasoline you prefer to fill your tank with - even to the route around the most recent orange barrels.

Obsessive-compulsives can put away the handwritten itineraries on legal pages, the stacks of travel guides, the road atlases and vacation brochures. Just slip a CD into your PC and learn a lot more than what your ETA is - ASAP.

Rand McNally's TripMaker Deluxe ($44.95 suggested retail) has been around for a few years plotting the shortest, fastest or most scenic route from Point A to Point B. But like a lot of personal computer software that has stood the test of time, it also has gotten better and better.

Now coupled with the power of the Internet to keep highly detailed information about accommodations and road conditions fresh, it can iron out a lot of wrinkles from a summer vacation road trip.

I tested it recently for a jaunt my family is planning this summer. I was so impressed, I made a decision to clear some valuable space on my laptop's hard drive and take it along.

It even works with global positioning system receivers, which use satellites to tell you your location any time, anywhere. (If I can figure out how to get my hands on one of those, I'll be testing that, too.)

Trip-planning software is just one way you can put a computer to work helping with summer travel plans, from shopping air-fares online to making hotel reservations by e-mail - after you've had a look around the virtual lobby, pool and room.

More on those options at a future date.

There's plenty to cover just in the electronic '90s version of the software as a valuable planning tool. For example, individual attention has been given to RV drivers who need services and to families with children.

Among the useful features:

Tripmaker Deluxe will modify your route if, after checking on road conditions via the Internet, it finds road construction or other adverse conditions.

Money Minder lets you search hotel and restaurant listings by rates, so you can stay within your budget. (Speaking of budgets, the software automatically creates one if you tell it how much you are willing to spend on meals and hotels.)

Headed for an unfamiliar address in a large city? Tripmaker will go to local streets in 82 large urban areas to show you your destination. Type in the address and it brings up the appropriate map. You can use the navigation buttons to increase or decrease the amount of detail.

Mobil Travel Guide offers one- to five-star ratings of restaurants and lodgings. Prices, hours, menus, etc. are available.

In the "fly/drive" trip option, you can use TripMaker Deluxe to make airline, car rental and hotel reservations on the Internet and have the software incorporate the information into your printed itinerary.

A "TripPack" printout option includes maps, written route information, travel budget and itinerary that you can put in a folder and stick under the seat. I even printed out information about which services are available at which exits along our computer-plotted route. It's the "Parents' Corner," a selection of back-seat travel games and activities, a list of attractions of interest to kids and a collection of rainy day options.

No menu for threats and punishments could be found by this reviewer.

One other feature offers parental diversionary tactics for the "Are we there yet?" and "Bobby's in my space!" and "He got to sit in the front seat all morning!" problems.

Dist. by Scripps Howard News Service