Alpha Self Storage in Cottonwood, AZ. In addition to traditional self storage units, we also proudly offer RV and boat storage parking spaces for rent. With a variety of sizes of RV and boat storage to choose from, you’ll be able to easily find the best option for your vehicle, be it land or water-based. RV and boat storage spaces range from 18-foot to 40-foot pull through spaces. All of our traditional storage units include a roll-up door for convenient access and storage. Traditional storage units range in size from 5x10 to 10x25 and include drive-up access.