I found this while looking for a place in Boston for the fall and I actually considered it, but my dates are booked.

http://www.greenturtlebb.com/

I don't think the idea is to travel in it...it's just for lodging.

Thank you all sooooo much for the great advise. Concurring the house boat questions, I did find some but they are tied to the docks, basically just a bed on water. I thought that going along the shore line and getting off at every port would be the thing to do (like a cruise). But I know now that is not an option. I really wanted to tour the city and the beaches, but appears it will be to cold in April. Any suggestions on the best time to visit when it's warm and not loaded with tourist... Thank you all again

Gail, thanks for the great itinerary. That's exactly what I needed. I visited Boston over 25 years ago for a few days and loved it. I have always wanted to visit again and stay longer. Great town. Thank you

"Any suggestions on the best time to visit when it's warm and not loaded with tourist."

Unfortunately, that doesn't exist in New England. "Warm" would encompass June through September there -- usually. And that's when the most tourists go there, and also when the locals are out enjoying outdoor and seasonal things. If a warm and maximum attraction experience is a must, I'd stick to these months and not worry about the people numbers.

Early to mid-June and early September are good times to visit because kids are in school so there are fewer families touring around.

You can look into buying the weekly pass for the subway (doesn't apply to the commuter rail) for $15. It's a good deal and you can buy it at subways stations or at the airport. www.mbta.com

Since you talk about being on the water, you could take the ferry to Salem in season, or take a day trip to Provincetown on Cape Cod on the fast ferry. There are also numerous boats that go to the Boston Harbor Islands, or that just do a short harbor tour. You can also go on a Whale Watch tour.

If you like museums, you should visit the Museum of Fine Arts and/or the Gardner Museum. Both have new interesting additions.