Nobody done this or have advice?
I did this trip last July with my son. It is really beautiful. I'm new to this site and am just figuring out how to use it, but I'll attach a few pics and give you some beta.
This is a really popular trip. Very beautiful, mostly above treeline. Bring your camera!
We did the trip in 3 days, not too difficult to do so. The loop we did was 31 miles (we took a short detour to Geneva Lake). We camped about 5 miles up from Crater Lake the first night. Lots of porcupines in our camp and all over that drainage (West Maroon Creek), I would not recommend camping there, they kept us up all night digging around our packs for salt. Hiked over Maroon Pass and Frigid Air pass next morning and hiked all the way to Geneva Lake. There is a very steep uphill for about 3 miles before Trail Rider Pass, it was really unpleasant in the heat of the afternoon. The hike down from Trail Rider to Snowmass Lake is unbelievably pretty. We hiked from Geneva Lake over Trail Rider and Buckskin passes and back to the starting point at Crater Lake.
Colorado is very prone to afternoon lightning. Be sure to hike as early as you can to avoid being above timberline by 1 PM or so. This a popular trip, you'll see a fair amount of traffic on the trail. Next time I go, I will plan to start really early (4 or 5 AM), hike up over Maroon Pass, over Frigid Air, and then camp in the trees in the Fravert Basin. That would be a long 15 miles or so, but it would be possible for a fit hiker. If the weather turned, you could hike down to the trees between Maroon Pass and Frigid Air, that would be a mile or so detour, not too bad. Geneva Lake was nice campsite and not crowded, I'd probably camp there 2nd night and hike out from there. Snowmass Lake is very crowded. You could do this in 4 or 5 days and have a very comfortable time, you'd just have to plan well to be in the trees by the afternoon.
Here is a link to a trip report (not my own) that you might find useful.
http://www.summitpost.org/four-pass-loop/327228
