My stepdad has a rusted 94 4-runner with 130k, He also just got a 2001 4-runner about 3 months ago. My concern is with the 94 because once he got the 2001 the 94 was just uncerimoniously parked in the woods line. The 94 has only even been started once in those three months and has not even been moved.

My question is: How long b4 time takes its toll on the 94 and things strt to break down from time and non-use.

Well, if Yotas are like Nissans, 6 months to a year inside a building, 3 months to 8 months outside.

Besides the mechanical problems you'll also have to worry about critters making homes in various places, especially when cool weather gets here. I had to put d-con in and around my Montero. Mice had made nests in the heater fan on 2 seperate occasions in the Montero and even once in the 4runner and i drive it everday. I found a dead squirrel under the engine cover of my mr2 a while back and a rat and a blacksnake under the hood of my 300zx several years ago. They chewed up some wiring in the Z. My vehicles become critter hotels in no time when they are parked.
Oh yeah, I also found a brids nest with eggs behind the grill of my 4runner.
I would at least fog the cylinders with something like rislone if the engine is good in his 4runner.