Welcome to BF. I myself am fairly new to this forum and am visiting ABQ.
I just rented a bike and rode it back up to my folks house in the heights and it wore me out! I've been doing 30+ miles back home, and a stupid little 4.5 mile ride was hard... go figure! Funny thing is, 25 years ago, when me and my friends were riding single speeds, it didn't seem so hard. Must be the age.... or the altitude.
Again, welcome to BF!