I don't know that land mass has all that much to do with it. Even in-state mail usually seems to take at least 3 business days if you're not paying extra for the rush.
I have the opposite experience. In fact, I stopped using Priority Mail because regular First Class tends to be at least as fast, generally next day within 100 miles or two days almost anywhere within California... for 49 cents.
(First Class Mail package is a little over $2 for 2 ounces.)
