Sorry former 60 owner no 80 experience.
When I was shopping for used Sequoia's a few things became obvious for fixes and things I have found since.
- Rear hatch latch mechanism can fail...more quickly in dirty or gravel road use.
- 4.7L seem prone to cracking exhaust manifolds
- not sure how great the paint or perhaps primer is on a sequoia. Rock chips seem to offer good starting points for rust spots and I don't live in the salty eastern areas.
- plastic headlight lenses prone to discoloration/clouding from the sun I think
- 4.7 has that timing belt and is an interference engine
- power antennas are prone to buggering up. My 03 has a solid one

2000 4Runner same failure
- electronics?? I have some interior lights not all coming on when doors open but function manually? some cold mornings VSC lights on? and my brakes seem to lack booster assistance.
- dash rattles need some attention
Certainly a nice riding vehicle as we took an autumn road trip out east putting on about 6000 miles. Surprisingly peppy for the weight. Not certain how it pulls as I had an 05 dbl cab tundra and trailering a 60 around seemed like a pretty good load on it.
The 05+ Tundras got the bump in hp and the 5spd automatic. Perhaps this affected the towing ability or not???