Can't tell you about the commute from Denver.
12/13 days off month on reserve.
If you can't make it they are pretty relax about it as long as it's not a constant problem and you give them a heads up so they can plan accordingly. No set rule about how many OOP (out of position) are allowed before they talk to you about it. If you can't make it in when you need to they tell you to get here when you can and call them when you are in base. They are very understanding from what I've seen as long as you leave yourself several options. Good luck!