A little late to the discussion, but Cape Cod is not my backyard, since I'm up here in Marshfield. With that said, my parents are in Chatham, so Sandwich seems to always be a good mid-way point for us. I'm surprised I haven't seen more postings of Beth's Tea House in Sandwich, not far from the Brown Jug and Daniel Webster. It's a sunny little tea room with delicious homemade pastries, cookies, cakes, scones, delicious quiche, sandwiches, and really good coffee. My mom does love the tea, so I'll go on her referral on that. The prices are great and I never feel rushed, so it's a lovely place to meet a friend for a chat and not get the angry glare for staying too long. Seriously, her display case of pastries and goodies reminds me of Charlie and the Chocolate Factory.
My mom and I love to have lunch at the Beacon in Orleans, but I think Cape Cod Guy has covered that great place admirably....I am just adding a little extra oomph :)
Is the Nauset Beach Club open in winter? If so, this place has always been solid for a good meal, and not necessarily just seafood.
How about Quick's Hole in Woods Hole? They stock some of my favorite wines by my friend Marco Montez's Urban Winery in New Bedford, so that was enough to draw me in. It's right near the MV Steamship Authority. Very fresh mexican, five or six homemade salsas....worth a try if you are there when Pie in the Sky is not open for a pastry and coffee.
I'm new to writing in to chow hound but not to using it, so please be kind if you disagree with my posts :)