I would start by checking out different marinas. Generally, most have a message board listing various boat services available such as cleaning, maintains and such. I would post a message stating your offer to pay for dockage in exchange for staying on their boat for a number of days a month. Also scope out where boats are stored if not at the marina proper. I find boat owners are a talkative lot and by and large nice. I would simply ask around. Right now is a terrible time to sell a boat, faced with a tough economy and the cost associated with boat ownership, this could a a win-win situation. My ideal boat would be cruiser 45' to 50' between 15 and 30 years old. You would expect to have 1 to 2 staterooms a good sized galley and a salon.
Based on the fact you are willing to live in a hotel, your "footprint" will be tiny and good sized locker at the clubhouse in addition to your space on the boat should be more than adequate.