Welcome to the forum from another Baltimorean. If you're looking to live downtown also check into the Anchorage in Canton.
I've heard there's a nice marina with an active liveaboard community down in the Magothy River. Not sure of the name right now, maybe someone else will chime in with that.
You might check out White Rocks in Pasadena. I'm not sure where they stand on liveaboards but their prices are good and the facilities are really nice, clean as a whistle. They're pretty understanding of DIYers.
Also, as always I have to recommend Maryland
Marina in Middle River. It's friendly, has a good DIY yard, and the facilities are decent.
Enjoy your new project
and welcome to Baltimore.