In-laws towing camper with 1994 Ford Econoline, 220,000 miles on van. While driving on highway, van "shut off." The electrical still worked, but engine would not start. They coasted to side of road, tried to restart, engine would turn over, but not start. My father-in-law looked under hood - said the air filter had "fallen down" and was on top of the engine, but was "disintegrated." Got towed. They were 800 miles from home. Repair shop looked at the van the next morning, and it started. Test drove. Could not get it to stall out. Recommended "tune up." Next day in-laws continued home with van towing. After 300 miles same thing happened while driving on I-95. Van "shut off." Got towed to a service station. Are sleeping in trailer in parking lot. Any ideas?

I would say it could. Especially for in town driving. It would help with the "searching for the right gear" that sometimes occurs at less than highway/open road speeds.

Also for any towing or heavier loads I would recommend NOT using overdrive.

For open road/highway I would use overdrive to get better MPGs.

Hope this helps.

have the fault codes read
possible
alternator belt broke
battery terminals loose
ground wire not connected

Here's a link to your problem.

Usually the problem is due to a dirty throttle body or a faulty idle air control valve. Stalling in reverse and not in drive is unusual.

Are you sure you tied into the factroy trailer wiring circuit of the truck? It is really hard to mess this up.

The "O" is the overdrive position for highway and normal driving.The other position is for towing and hilly highway where you need power acceleration and avoid downshifting.Once you select the drive range, it's automatic.

sounds like faulty ignition coil.

If it always starts back, it may be your MAP sensor. If so, it will cut off going 10 miles and sometimes 40 miles before it does.

Relay

57k miles on a '94, nice...
The transmission should be able to handle a 500lb load and a 500lb tow, you really shouldnt hardly even notice the weight unless you going up some steep grades.
as far as what to look at before going on a long trip, diffenetly get a oil change if you havent in 1500'ish miles (or get one on the road when you get closer to the recommended mileage of 3k miles, which you should hit easy enough on a 11 hour drive to your destination) Perhaps plugs and wires if you havent had at least 1 tune up since driving off the lot. all your fluids, bulbs, fuses(bring extra fuses with you), at least 1 spare tire, tire pressure(35-42psi), and anything else that is general maintance that needs to be done also.
Other then that, you should be fine... Just dont forget to check the gas gauge once in awhile, and she shouldnt die on the way :P