Maybe you should think about something like this:

http://www.oceankayak.com/kayaks/sin...yak_board.html


It'll fit into your van, be fine for the monocacy or around cambridge - you won't be a speed demon on it, but I don't think you'll be one anyways

REi's got it on a bit of a sale, not sure it'll be there in october when you're ready to buy... benefit of rei is that if you try it out & don't like it... you can return it. free shipping if you pick it up in store.
http://www.rei.com/outlet/product/793958