You can buy small propane bottles at St. John Hardware. No place in Cruz Bay to buy cheap towels. Suggest that you might want to stop off at KMart in St. Thomas before you come to St. John to pick up some towels. Check with Cinnamon Bay they might have coolers for rent. There may other supplies in the store there but I have never seen propane there. I'm sure if you contact them they will give you more information.

I stayed at Cinnamon last November in a bare site and in a tent cabin in March. I just used a sarong for a towel, lighter and dried quickly. I'd pack a compactable soft cooler, can pick up ice and propane cannisters at the campground (a little pricey) but found I really didn't cook much. Bring at least one large heavy trash bag to store your stuff out of your tent (please don't forget to pack your rain fly like I did). You'll see the people who have stayed there before have an intricate arrangement of tarps and ropes to do a canopy system. One idea I loved was a couple who had the glow-in-the-dark sticks and hung them outside their tent... that way we could see the path to our site... gets dark early. I loved my magnetic tent light to read by. You'll love it, my only decision last fall was whether to walk around to the right or left of the tree to get to the beach... 28 steps! The beach is abandoned at sunrise, it's all yours.