John and Grayle,
Welcome! And congrats on your new C-Dory :thup As Pat mentioned, the Lake Powell cruise leader is from the San Diego area, so at least one other boat will be heading the same direction. People do tend to come to Powell from all over the map though.
I am hoping to be there - it's really fantastic (as you know from your previous trips).
One odd/funny thing about a bimini at Powell (for me anyway). I'm usually the type that always likes "roofs." I tend to like porches, and on most boats always have the bimini up, and/or like to hang out in a semi-enclosed space. I'm not one for the open cockpit. But on Powell, even though I have a bimini, I didn't put it out even once. I loved being able to look up into all the amazing canyons as we puttered in and out of them with nothing over the cockpit. I guess because the weather is mostly conducive to having the door and windows of the main cabin open, the cabin roof was like the bimini, and then the cockpit was good totally open. Too, it wasn't the hottest of years, so that may make a difference. The previous year I was on another (similar) boat and we had a golf umbrella type of setup. I just mention these things in case for some reason there is a crunch getting a bimini specifically for Powell.
That said, there must be some great canvas makers in your area. It seems like the best option is a good local canvas-maker, with "the other option" being to buy a pre-made one from King Canvas (they made many of the "stock" ones for C-Dorys, so I think they will make them without having your boat there, although I'm not sure.) I think I would prefer an excellent local shop though, myself. I think the 25 "Dora~Jean" has some really nice canvas that was made in the Los Angeles area (you could check his album), although I realize that's not exactly San Diego.
Sunbeam
PS: I just remembered you said you were new to the site and getting used to navigating it, so here is a link to Dora~Jean's album. He had the cover (in the photo album) made at Van Nuys Canvas , and it looks like perhaps the bimini too. When he talked about it in a post I got the feeling it was a great shop. The cover certainly looks nice. If you want to get in touch with him you could PM him.
http://www.c-brats.com/modules.php?set_ ... _album.php