Would you still suggest pants for orienteering out in Wyoming, or are shorts ok?
There is sage, I would wear light pants.
Lots of people wear shorts and gaiters. Personally, I like light but full length pants for that terrain.
Do you want to use your legs again, or are you just going to discard them before the trip home? If the former, then you will want to find the most rugged jeans you can, and get two pairs. Wear them both at all times, even in town (you could tumbleweeds there.)