Lived in Denver area for 56 years and didn't know El Monte RV even had a Denver metro rental location. Just shows you're never too old to learn!
Regarding Class C size, how large is your family? Both the CA 19' and El Monte 22' have about the same amenities. If you have kids, I would pick the one with the biggest fresh water, gray, and black tanks and fewest beds to "unmake" into a dinette during the daytime. This will ease dry camping at campgrounds inside the parks and give you more time to enjoy the sights. And because those kids will be sitting for long periods, the one with the most comfortable, best viewing seating area would also be important.