If the group goes/makes it all the way to Buck Island lake, you may want to stay 2 nights there and have fun with it. there really is no where inbetween BI and Rubicon spring. Back when Spider lake was open, it made a easy first day(camping at spider lake), then on to Buck Island lake, then into the springs. Now that Spider lake is closed for camping and such, it make a long day into Buck Island. Any how if any one breaks down(knock on wood) or the trail goes slow, you may end up camping just off the trail in what area you stop at for the night type of thing(meaning camping in other than camp area spot). With some of the faster groups on the trail, the going can be real slow down the big sluice. Meaning a long line to get trucks down the rough stuff, which can take 1/2 hr per truck to worm it way down that area to the bottom(or more).
At buck island you may want to go back up and try Old sluice and play on the slabs for a day before going into the springs. Some of this may be decided once on the trail with options left open as the trip plays out.
Any how there is some hikeing and talking with a bunch of other cruiser heads, taking ride and drives in a FJC. Chaseing crawdads in the water, soaking in the cold springs, the rope swing that drops you in the lake. Lots of other fun stuff as well, playing on some of the run and the obsitcals in and around camp.
Stuff to think about.