Yup, good tip. Too bad I just moved away from Longmont, I'd have been happy to meet up and put a pile of stuff in front of you guys. I don't have a USP to show you though.
Check out Front Range Gun Club in Loveland. They have a decent but not huge rental selection, and they are very welcoming to women, not condescending or patronizing; and for the proof in the pudding they do have a pretty active women's shooting league, as well as a couple's league. Friendly folks, and it probably wouldn't be hard to get your hands on a lot of diverse hardware if you ask nicely. Members only, though you can go in twice under their "explorer" program, and their league shoots are open to non-members.
Closer to home, I know of two ranges in Longmont. Trigger Time Gun Club, and the Longmont Police range (which is open to the public). I've never been to either and I don't know what if any rentals they have. Both are on 119 just inside Weld County, on the way to I-25.