What's all the rush? You've only got a 7 days, so why not enjoy them?
If you want to head west, then set your sights on Cuttyhunk. This should prove an easy day trip from Buzzards Bay. I would think spending a day there, exploring the island, and chilling out, could be fun.
From there, continue on New Bedford. If you haven't visited the whaling museum yet, its a great take-in. I've also read that the city has done a lot in recent years to be more welcoming to cruisers. Once again, a day to get there and a day to enjoy.
From New Bedford, starting heading home. There are quite a few picturesque harbors along the way to pop into, like Mattapoiset and Marion. Here you can spend another day or so. You vacation is nearly over and you haven't had to kill yourself.
The purpose behind my suggestions is to encourage you not to adopt the "This is Tuesday, so it must be Belgium" mindset, but to slow down and smell the roses.
Have a safe trip and watch the weather!