These trucks are popular and holding value extremely well. Ive seen a couple extra cabs lately with under 100k mi., asking in the $20k range, crazy.
You could probably sell it same day if you weren't concerned about the future use of it. I get asked somewhat often if I want to sell my extra cab. Last one was a guy wanting to send it to Mexico. While I love the truck and have owned it 18+ years, in the end, if and when I do sell it, the $ is all I care about. Even the most caring owner could crash it the next day.
Best of luck with the sale, even with the high miles you should get a good amount.