The first mile or two won't be too bad, but after that you'll hit a couple of miles of hard and rough blasted granite on a moderate climb. Make sure you have two pair of thick wool socks, monitor hot spots, keep boots tight enough to avoid feet slipping around, but not tight enough to cut off circulation in toe area.
I haven't been in this season, so can't give you a report on current snow & water level or bugs.
I agree you seem to be a bit long on miles. As you are going solo, you benefit from a loop. I have posted some other maps recently for various Desolation loops; I'll dig up links. I'd cut this down a little. I like to create routes that have alternate quasi-parallel trails that include some that are shorter/easier in case my group needs to take it a bit easier, as well as some alternates that are longer and have more to see if we are doing better than expected.
One minor adjustment I'd recommend for the beauty is to take the trail to Dick's Lake, then a use trail to and by the edge of Fontinilis. At the outlet of Fontinilis, stay just on the right side of the stream and follow it down the granite pluton (it's a little steep-but not too bad-just stay off the wet part). This is a very pretty stream cascading down the side of the rock. At the bottom, just keep following the stream cross-country through flat forest until you rejoin the trail. This is high Class I off-trail at worst and worth the very short distance that you are off-trail. In that you're going solo, however, you need to let specific other people have a detailed route plan of where you intend to go and where you
might go. At your experience level, you should not deviate from that plan at all. If you go missing, others will know where to look. You need to have someone you are going to contact by a certain time, and that person needs to be ready to contact authorities if you are not back by that specified time. I will be back shortly and attach links to the other loops I have suggested.
By the way. This is an area where someone going solo can hitchhike between starting and ending points. There is an endlesss stream of cars and many stop along here, so I'll include some other possibilities as well.
O.K., back with a map. Here are a couple of 3 day possibilities.
Loop out of Glen Alpine. Start at the other trailhead that's east of Lily Lake. (Call first to inquire about trail condition. Has anyone here been on this trail recently?) Hike SSW to Tamarack or Ralston for 1st camp. Day 2: to Susie as shown. Day 3: to Gilmore, leave pack, climb Tallac, return to Gilmore for camp. Day 4: exit at Glen Alpine. Do a side trip to Half-Moon if you have time.
Hitchhike assisted route: Start at Meeks Bay and go to GIllmore. (Crag is < 1 mile more and has better camp sites.) Day 2: go to Phipps Pass and either camp just below the pass on the other side in the swale where the stream begins or XC down to N side of Phipps Lake. Day 3: to Fontinillis or Dicks Lake. Day 4: out at Eagle Falls (Emerald Bay) and hitchhike back to Meeks Bay.
Map:
http://caltopo.com/map?id=0376" onclick="window.open(this.href);return false;
With a group, I like going to remote places and not seeing others. When going solo, the advantage of going where there are many people is that if you get hurt, there are people around who can help you. The east side of Desolation has more people than the west side.