I'm in a similar situation, going to go check out a '87 runner today and, with any luck, it'll be in my driveway tonight. So far my plans are modest: first I plan to get it running well, which shouldn't be too much trouble. Owner says it needs a new clutch throwout bearing and the wheels need balancing. Once I get all the little mechanical and electrical gremlins taken care of (which I'm hoping will only be a weekend or two of work), the next step will be the appearance: getting rid of the rust, cleaning out the bondo, giving it some fresh paint, that kind of stuff. That will probably take a little bit longer, but I'm hoping to have it done before winter gets here.
Hopefully by the time I'm done with all of that, I'll have enough saved up to start with a couple of modifications. I was hoping to start with a solid axle swap, and replacing the rear axle with one from a later model v6 runner/pick-up. It's my understanding the rear axles from the v6 models and the earlier 22tre's were a little more stout than the ones that came with the regular 22re. Still trying to keep with the stock Toyota pick-up/runner mechanicals so maintenance doesn't become a nightmare. While I'm dinking with suspension I'll probably be throwing in some taller springs and getting some lower gears at the same time. I also saw a runner for sale on here not long ago that had a custom rear bumper with a tire carrier that looks like it might be a more sensible place for storing a full-size spare than the usual undercarriage mounting rig.
And if I've still got money leftover after all of that, I've sort of been toying with the idea of trying to find a 3L diesel engine. I've heard that's what they were putting in the foreign market 3rd gen 4runners, but haven't really looked into what all I'd have to do to get ahold of one or what sort of issues I'd run into to get it running.
I hate listing mods like this because usually something will come up and I'll not have money to do them. With my budget, I'd probably not have the funds saved up for the big things like the axle swap until this time next year. I(n the mean time, I'll just be picking up the parts here and there as the funds become available. At any rate, I've already bought the new shifter knob, so it won't be a complete loss.
I don't know if this will give you some ideas or not. My plan is to run this truck mostly as my daily driver, but I wanted the extra seats in back so when we go camping, I can take more than one of the kids with me. Definitely I'll be taking care of the rust issues before winter gets here; I've got a buddy that bought my previous truck, a '90 x-cab pick-up. Both trucks are black, and both have rust issues, so we'll probably end up doing them both at the same time to save a little cash and use each other's scrap material.