We try and do the same and support CW and up to a few years ago we did purchase from them online or from the B&M stores until they began upping their shipping charges beyond ridiculous. We still renew our Good Sam membership, rarely do we get any savings out of it since we don't do private parks much.
Use primarily Amazon and Walmart, they will ship anything to their stores for free. Something CW should be doing as it will certainly increase foot traffic in their B&M stores. I always seem to buy something else every time I go to pick-up something from Wally's ship to store dept.