Dachindae Atlas

I really want to go look for some Heterodon nasicus in the wild. I'm in Wyoming but I'm afraid I'm a little too high up in elevation to see them. [7,200ft...]

I really want to collect just one and take some photos of any others I find. Is there a really good spot to look for them maybe close to Ft. Collins or Denver? I might take a 3 day break from work to go field herping, haha.
And what time of year? It's still bitterly cold here so I think I'm going to have to do some driving to find any.

I've also never gone field collecting before. Things I should know before I try it?

Any advice would be great!