I bought a 2010 crewmax 3 years ago with 105k on it, and I'm at 165k now. Done basic maintenance, the power steering blew last year which was a bummer, and I upgraded to bilstein shocks but otherwise it's been great. I added a leaf in the rear to help with sagging under load, it was a great fix for $100.
I'd like to figure out if I can solve for the front chains without any spacers or such.....but I haven't had to chain up yet. A smart man would at least practice/test on dry comfortable conditions.
One other thing I did was put a receiver in the front, they're like $150. I then ran power for my winch to both the front and back, and put it in a receiver winch mount so I have flexibility. Sometimes it's a pain to carry in the bed of the truck, but when you can hook it up on the rear, it makes it nice.
3) Mine is an SR5, but with leather, power seats, intermittent wipers and such which is unique, but the SR5 badge controlled the price.
4) I'm not a fan, I've debated on a locker, but not worth the investment.
5) Shortbed on the crewmax, but I also love the very large backseat, so flip a coin.
6) As noted above the power steering blew, which sucked, but otherwise it's been at a basic level.