So many different swaps you could do, how much money you got??? :shrug:
Keeping it toyota makes for an easy swap, you could stuff a 5MGE in it, stock around 140hp, or turbo it (they work very well with a 7M turbo manifold and CT26, stock ecu handles up to 450hp). that engine used a W 5x transmission, I've seen it bolted to the stock truck's tranny (a W56 should be in yours), so no adapters needed.
You could spend a bit more and stuff a 7M in there too, slightly more work than the 5M, but gain more hp. Those also came with a turbo version, if you feel like spinnin' tires everywhere, that's the way to go!
3RZ/5RZ would work well too, there's kits out there to do the whole thing, but you'll be doing a lot more work to swap it all over, and it makes more sense to have a donor truck for the swap.
Chevy/Ford conversions are also out there. I'm not a fan of NWOR, but they have been around for decades, and if anyone has more info on a chevy swap, they would be the ones to know:
Toyota Engine Adapters, Ford, GM, Chevy V6, V-8 Conversion Kits
Diesel? Yep, you could do that too! It doesn't have to be that slow either! 5 cylinder merc swaps are fantastic, especially if you turbo that beast! Lots of money to do "right", but the end result is god-awful amounts of torque and fantastic gas mileage too!
If you wanna stick with a 22RE swap, there's a ton of guys out there building great 22RE engines. I've had a TCPerformance 22RE in mine for many years, the thing has tons of power, considering that I have 35's and 4.88 gearing, yet I can hold 90+ on the highway, and if I keep it below 60mph, I can pull 20mpg.
Wanna get crazy? Stuff this thing in there:
22R/RE Stage 5 Pro Stroker Race Long Block
400+hp from a 4 cylinder toyota engine? Only if you got 8 grand to play with!