What sorts of things are you interested in seeing? I love the cape but it may not be impressive to you coming from the west coast. I would suggest a trip to Acadia National Park in Maine if you are at all into hiking. There are also some great mountain drives in Vermont and New Hampshire. I would think you would see more of the classic New England that way.
If you are set on hitting the Cape, I would suggest the outer Cape. You could use Wellfleet as your base camp and explore Truro and Province town as well as the National seashore. I would be happy to provide any information I can depending on which trip sounds more interesting to you.