Advice/Critique on Maroon Bells 4 Pass Loop Itinerary

I don't think its overly ambitious at all. Your miles are low. You could do it in 2 d-3 days easily, but take your time and enjoy if that is your preference. There is no problem hiking in the 11-5 hours, and your trip into Maroon Valley is so short it won't matter much. You have rain gear if it rains.

I have been doing more and more reading about weather in this area in August and it looks to be monsoon season. Everyone says to stay off peaks from afternoon to evening which means I should be sure to descend from all passes early in the morning. My main concern is my second day going over West Maroon Pass and Frigid Air Pass. Can anyone comment on if leaving around 7 AM on my second day will give me enough time? I know it's hard not knowing my hiking speed and all, but if anyone has done it and can leave their experience that'd be great.

Unless you've got plans in Denver, I'd suggest staying there one night then staying higher the next night. Might as well see how you're feeling just staying at higher elevation before you start. Especially if you haven't hiked at those elevations before. If you can, get a camp site in the Silver Bar/Bell/Queen campgrounds. (If those are booked, there's another campground just south of Aspen that usually has spots. Can't recall the name at the moment.) You can see how you feel before you start and you can get an earlier start.

But 5 miles will put you pretty close to West Maroon Pass (about 1.5 miles). Once you get over West Maroon, you don't descend much heading over to Frigid Air so it's not a long haul up like the other passes. It's probably another 2-2.5 miles from West Maroon to the top of Frigid Air so you should be on the way down by 11 or 12 if you start at 7. If you're concerned, start at 6 and give yourself more time.

Also, and you should probably call to check this is still true, if you tell them you are backpacking at the entrance they'll let you drive up to park. Otherwise you have to take the shuttle in the summer.