You can do a lot to these trucks with $2000, assuming you are doing the work yourself, or have good deals with someone who will.
If I was throwing $2000 at my 4runner, I'd buy armor, new rear springs & shocks, bj spacers, good 33's, and a rear locker.
Someone here has a 4runner soft-top operation going. The bikini top is ~$300, and looks very well made, and most importantly, cool!