I had a 2000 and now have a 2005, and the 2005 is worth the investment if you can swing it. You wouldn't think the small gain in power would cause much improvement but, probably with the help of the 5 speed transmission, it doesn't feel underpowered, which the 2000 often did.
It is a pain that a later years pretty much preclude aftermarket nav and audio systems. That said, though, if you have to be stuck with a factory system, they're pretty good.
I've said it often, but I'll repeat that I don't think there's a truck that will serve as well as both a daily driver and a serious overland vehicle. You can have big tires without a lift, the height control will give you plenty of clearance, and while the AATRAC may get stick from the most hard core wheelers, for overlanding it is a very nice system. You will want to exchange the fiberglass running boards for something less breakable. My truck has MetalTech sliders and I can't see how they could be better designed; the women in the household find the slider just perfect as a step.
My major point, I guess, would be that the 100 is a vehicle that can be your wife's daily driver and your overlanding vehicle at the same time. That's how we've done ours. For most of the time, it's just another cushy mall crawler, but by just putting a roof rack on the top and figuring out sleeping space in the back (try here:
http://www.expeditionportal.com/forum/threads/77938 for one approach), you're set for all but the worst terrain.
