3.0's are too tight in engine compartment, harder to work on and has more
troubles than 22R-E.
Stick with 22R-E 5-speed. Automatic transmission robs power and harder and more expensive to work on. You can trade your starter on a 5-speed manual for beer or steak on the trail and still be able to start your engine - LOL!
First-gen 22R-E MANUAL transmission has fewer critical problems, mostly wear and tear items, so much easier and less expensive to work on compared to other trucks.
Radiator / cooling system may have been neglected so clogged and less efficient. My head gasket blew o@ 1pprox 180,000 miles, one year after I bought my 1986. Test going uphill in warm weather.
Sagging rear suspension. There are fixes ranging from maybe $50 for "Zuk mod" to $1500 for Old Man Emu leaf springs.
Expect shocks needing replacement, just from normal age. The common push down on bumper several times the release to see it bounce does not expose bad shocks.
Check steering components, especially the idler arm - normal wear and tear.
Ball-Joints may have play (especially upper ball-joint that carries more load than lower ball-joint). Would need replacement (easy process), but not likely to lead to catastrophic failure unlike 3rd-Gen
Intermittent click but no fire is a good problem to find on prospect. (search "Clicknostart 22RE" You can use it to bargain but is easy and cheap to fix using relays or simply rewiring
Dim headlights, also inexpensive fix, using relays on "H4 conversion harness".
Weak horn, also easy to fix using relay and possibly replacing contacts in steering wheel.
"Alexman Videos" on youtube cover a lot of fixes. Also LC Engineering and 22RE Performance.
Parts are often less expensive than other models.
Sources:
LC Engineering
22RE Performance
Summit Racing
Toyota Parts Deal, etc.