Before I bought my house in Lake Havasu, we used to go to Martinez all the time. We'd always rent the mobile home with the dock out back, and just leave the boat in the water. I'm pretty sure it had a BBQ too. http://www.martinezlake.com/Rates.htm
I think it was C-58.
Back then, accomodations in Martinez were basically trailer-park-style, with dirt roads, but you could find glassy water all day long, so that more than made up for it. From the looks of the pictures I've seen, the town hasn't improved much.
Hint, unhook your boat in front of the restaurant. If you try to pull up to the unit, with it, you're going to be backing out a long long way.