Thanks for the shout-out, Bart!! Yes, I write a lot on TA about Lake Powell, but I've got to say the level of knowledge about Lake Powell on the WaynesWords forum is humbling... super knowledgeable crowd here from many perspectives...
As to the houseboat sites in the Escalante, I agree with Bart's assessment. Not too many, especially on the main stem, but the best ones in the side canyons are choice. The one Bart mentions in Davis Gulch past LaGorce Arch is one of the best on the lake, but is only there if the lake is between 3605 and 3630... which in May it might be at the low end of that...
As for Fifty-Mile, if the lake is below 3605, you're going to be stuck getting past a giant sandbar blocking the whole passage about 0.8 miles from the mouth (which is also a good campsite), but above that lake level, there's a few good houseboat spots for another mile or 2 before it narrows too much.
Other side canyons have their own sites, but much depends on the lake level.
On the main stem of the Escalante, here's my past notes for the inventory of good houseboat campsites, depending on lake level:
- One of the most reliable is right near the entrance on the right, about 0.4 miles in from the main channel, where a small beach may yield a site or two, especially at lake levels below 3610, when the beach grows longer, up to about 800 feet.
- There is a possible beach site in the first cove on the right, about 0.75 miles in from the main channel, perhaps best between 3590 and 3610.
- Rocky beaches line first inlet on right 1 mile in. The inlet is about a half mile long and 500 feet wide.
- Small beaches are in second inlet on right 1.2 miles in from the main channel (0.4 miles long), across from the mouth of Indian Creek, which might be best at lake levels between 3620 and 3660. There is a site at the entrance on right, and potentially one at the very end.
- There is a small, steep, rocky beach on left just before Clear Creek at most lake levels.
- There is a 150-foot long rocky beach on left in the bay upstream from Clear Creek, west of an island about 1 mile past Clear Creek.
- There are two poor rocky beaches on the left in the bay 1 mile past Fifty-Mile Canyon
- There is a very marginal rocky beach in the bay on right 0.6 miles past Willow Gulch, and a 400-foot long rocky beach just after that.
- Beaches near Garces Island and mouth of Explorer Canyon are possible at lake levels above 3620;
- Beaches at the mouth of Fence Canyon are possible at lake levels above 3650.
- Beaches 0.3-0.5 miles past Fence Canyon may be possible when the lake is near full.