Yeah those newer trucks have definite head gasket issues. I think it's usually number 6 that fails. Not a huge deal if you know what you're doing and can put in the time/money but still...
Transmission and t-case are mostly solid, but I'd do a part time conversion right away and then locking hubs on the front axle, a lot of these trucks have birf issues because of the full time awd. And they'll wear out chromos in a short order. Probably plan on rebuilding the front axle.
Sorry maybe I'm just jaded, they're still good trucks but they have some definite things that need attention.
And Ih8mud sometimes really pisses me off. Plenty of guys over there who would crucify you for introducing Dana axles or a chevy engine etc to the Land Cruiser... Toyota purists.
This thread exemplifies a lot of my distaste.
Anyway, don't let me turn ya off from the truck, if you know what you're doing they're still cool.