This is a great online map of powell with descriptions of bays and such.
http://www.elakepowell.com/freds/lastchan.htm We houseboated in '03, staying in face canyon.
I may have the GPS coord still in my GPS, but the maps should help. It is about 2 hours by houseboat from wahweap. From our campsite near the end of face, it was 30 min or so to either wahweap or dangling rope marina (driving about 30 mph).
Our spot was perfect, it was the last place in down the canyon for a houseboat, so no other traffic came down. Just around the corner from our site the lake opened up to ride, while being protected.
That is a great time of the year to go. Have fun and I hope your mom feels well.