Have you had it inspected by a yota dealer yet. From what I've heard the worst years are toward the middle of the spectrum, as in lots of bad 98's and 97's and less bad 95/96 or 99/00. I saw the breakdown somewhere on the monster of a 60 page thread over at ttora.com
I'd say if it looks good now grind off what you can and coat it with something. Lots of failures occur at the front mounts for the rear leaf springs.
RIP CJT 3/20/74-06/27/01 Never hold back your feelings cause you may never talk to that person again.
RIP MPT 6/2/79-5/22/08 I will forever ski with you by my side.