A few years back, my little sister and I planned a 4 day trip in the S San Juan Wilderness area.
Starting at the west end of FR247 (west end of Platoro res),
we headed west on TR712 (following Canejos River)
Staying west, headed up middle fork (still TR712--but there is an intersection there--well marked in 2001) and up to Lake Ann (spitting distance to the continental divide).
Then south along TR813 which took us up to the divide and stayed there until we got to Blue Lake.
Then south on TR718 to Green Lake
North/east on TR725 (Canon Verde)
N/W on TR724 (south fork of Canejos River)
North on TR722 (canon Rincon) to Glacier Lake
TR 723 takes you back west to Blue Lake
From there, head north on TR718 which will bring you back to TR712 (where you made the turn up middle fork on the first day), and back to the trailhead.
It was supposed to take us 4 days, but we were forced out due to injury and weather on the morning of day #2 (we camped at Blue Lake--but I suggest Lake Ann, otherwise it is a long day). Overall, I think the planned route was just shy of 40 miles...
All of the above trail numbers are as listed in the Colorado Atlas & Gazetteer. We did see a couple of people when we were out there, but not many. Some were fishing...but didn't have any luck at the point where we crossed paths (2 guys fishing @ Lake Ann, and one guy fishing about 1/2 in from the trailhead). Trails were in good shape, and easy to follow...with the one exception of Middle Fork--as it approached the divide, the trail faded to nothing, but we could see TR 718 in the distance, so there were no navigational problems. Not sure what the trails are like south of Blue lake--as I said, we skipped 1/2 of the trip due to minor injury complicated by lots of rain. Oh, we did have to hike across snow drifts--in August....and we had one bear come through camp....but no major logistical problems.