Thx for more background; I am familiar with the 4-way intersection, I always come from the north ("straight"), I was aware that "right" (E, right coming from south) goes up to 67, but never rode it. And I have never tried the W branch, but I can see from satellite how it hooks back up to the N branch.
I dont' think I have a skinny tire problem as my two CX options are both 2" wide.
I see from satellite that there are trails on the W border of the lakes, I was looking at the E side, either the asphalt inside the park (but don't know whether I'd have to jump a fence at any point to get out), or Fanita to trail which seems to parallel all the way up the lakes no more than 100yd away.
I think what I'll do is this Sat take a probe ride, see if I can find my way from the N to the top of the lakes, then I'll know better firsthand whether (monster?)cx can handle it.