So the MUP is too crowded? Then umm, don't ride it when it's crowded. A 4:30am start is pretty much a guarantee you'll have the whole thing to yourself.
I didn't see anyone else on a bike, and didn't see another person until I was almost home.
Not that the SART is ever particularly crowded anyway. I have no complaints. Well, that's not true. If the "homeless" encampments could break their glass bottles down in the riverbed instead of on the trail itself, that would be pretty great.