Ford F150 with the straight six, longbed, and extended cab? And 4wd? If this combination was made, it will be slow, but I never feel compelled to drive trucks fast for some reason, so why does it matter? Get a cheap, likely mismatched topper, and you instantly have a place to sleep.
There are always a few F150s on here for cheap.
We had a F100 with the Ford 300, 4 speed, 4x4 as a hunt-camp truck... that thing was unstoppable.
Jeep Cherokee. The only modification you need for sand is a set of tires. I'm running my $600 XJ through sand and light mud with trash tires. A set of real off-road tires will allow you to keep up with anyone. If you must have a bed, look for an MJ Comanche. I can keep an eye out for you here in Palatka and on the Jeep boards. $800 will buy a decent one of either. I overpaid for my Jeep by about three bills, but deals are out there.
Oh, and you can keep all the tools you'll ever need in the glove compartment.
+2 for the F-150. I owned a '90 4X4 XLT I-6, EFI 300 cube, E4OD, 355 axle, towed 3500 lbs. well w/ tool boxes n spares in the bed, good snow/ off roader, 15" tires were cheap enuf for sets of winter/ summer or off road. Extra rims cheap too.
Liked it so much I bought another '90 XLT 4X4. EFI 5.0, 5-speed, 410 trac-loc axle.
These were great trucks. In the Northeast they will rust up in the cab corners, wheel wells, rockers... the usual suspects. Watch the inner pass. side u-joint, have to drop the front punkin' to remove that one, rest are ez. Southern truck bodies are prolly no problem. '80s engines had a problem w/ piston skirts breaking.
A fiberglass kick up shell worked great for race weekends and camping, even the cab seats was comfy for sleepin.