To ensure your transmission doesn't destroy itself from lack of lubrication, you have a few options, if your truck is rear wheel drive.
(1.) Disconnect the driveshaft at the differential when you tow it.
(2.) Install a driveshaft disconnect link in the driveshaft.
(3.) Install a lubricating pump to circulate ATF as you tow the vehicle.
Note: #3 will also work if you have a front wheel drive truck. #2 isn't available for front wheel drive vehicles.
Drive Shaft Coupling
Remco Lube Pump Kits | $150. off & free shipping
The components of either #2 or #3 will cost about $1000, another multiple hundreds to have installed, not to mention the base plate, brake system, and lighting modifications.
You are talking about cost and labor of perhaps over $3,000 for a truck that is 18 years old. Unless you can do the work yourself, I'd think seriously about buying a vehicle that can more cheaply be modified for towing.