I use Colonial all the time and it works fine as long as you call ahead and get reservations. The only drawback is that the van that picks you up from the terminal is always packed, usually standing room only.

It's $7.50 a day with the coupon from the internet and you can also get a frequent parker card with gives you a free parking stay on every 8th visit, up to 5 days parking.

One other drawback for you is that you will be coming from the north on 95 not south, so it's a little out of the way for you.

I drive a Prius too, so I understand the whole key thing.

Rich