Good Evening,
I keep mine at Parker Oil's VIP Storage on California, just over the bridge. They own Lakeland Marine in Havasu (I think); I've never used them for service, but I think they would tow/bring the boat up and back for you. They have abot 40-40 ft spaces with cement outside, not gravel.
928 669 2617 ask for Rene for storage issues.
Take care.