I have a '91 with a warmed over inline, NP435/205, 3.08 factory axles, and 32" STT. I beat the the hell out of the truck when I wheel it. I tear fresh motor mounts in a weekend and have yet to break an axle, it is open front and rear though. I have had zero issues at Twisted, Mounds, or Silver. The TTB will flex in the rocks, the rear leafs are super soft and flexy on mine, for general off roading the TTB isn't a bad design.
For what it sounds like you are doing I would:
Swap the M5ODR2 out for a ZF-5 from a F250 or F350. The Mazda is not the worlds strongest transmission and includes horrible ratios. The ZF-5 has a creeper first gear and a much lower reverse ratio. This is a direct bolt in swap, the transfer case is plenty strong. Write up on the swap http://www.ford-trucks.com/forums/11...t-bolt-up.html
Stuff 32's or 33's with some fender trimming. I thought about running 34x9.50x15 TSL narrows.
Lock it in the rear. A lunch box maybe all you need from the sounds of it.
Skip plates and a winch.
Low budget, very capable. I have surprised many people with what my truck will do. I usually follow a XJ with a 4.5" long arm and 35's around in the parks.
Oh and get rid of the factory automatic hubs for a set of warn lock outs.