We've been going to Powell for 15+years... We were just there last September.
Been there when it was full and when it was 90+ ft low. Biggest thing to watch out for is rocks and such being very close to the surface when the levels are low.
Maybe you know some of these things already but here goes...
Always stay more towards the center of the channel while traveling in the house boat and never cut close to the shore going aroung bends. When your getting ready to park/shore the houseboat if you have a smaller boat or jetski, scout for rocks and dibris near the shoreline to avoid tagging a prop.
Every great once in a while the wind can be quite strong so always set 4+ anchors for the houseboat (more the better) and set the rears wide and not super tight so the boat has room to move a little.
Place a stick in the shoreline at water level and watch how much the water goes down during the week, sometimes backing the houseboat off the shore a little mid week helps when its time to leave.
Depending which marina you go out of there are great river arms to setup camp in, we always head down to the San Juan river arm because its deep and has some nice spots.
Try to plan out all your supplies so you don't have to go back to the marina during the week (gas prices there suck). If you do, travel in the morning as thats when the main channel is less busy and more smooth.
When you pick up your house boat have them show you that the toilet system has been pumped empty, you don't want that filling up mid week. Trust me we know this from experince... All grey water is now captured in the storage tanks so try to limit showers indoors, water running in the sink (use dish washing buckets and dump it outside) and pee outside as much as plossible (we call it checking the prop). haha
LOTS of sunblock, the glare is brutal off the water...
I'll think of more but my lunch hour is over so gotta go for now.
