Fair enough. I think you have to actually contact marinas
for pricing info, but I'd suggest you maybe look at Bert Jabin's, Annapolis
Landing, and Port Annapolis on Back Creek to see if they mention whether allow DIY. If not listed, that might require direct contact, too.
Holiday Point on the South River would be another possible choice. Both convenient to WMs (and Fawcett's nearer the Back Creek places), although the WM in Edgewater (closest to Holiday Point) isn't huge. Liberty Marina further up the South River might be another choice to check.
Herrington Harbor North in Deale has an on-site WM, in case you're willing to be that far away from Annapolis. Great marina.
Yes, prices on the South River (for example) are generally lower than Back Creek.
I doubt anyone even notices that kind of short-term liveaboards, but I think several (maybe most) of those marinas may have some full-time liveaboards anyway.