The U-Store-It sheds. Regardless of the name the company calls itself you rent a small room by the month or year. They are meant for storing extra furniture or businesses store old records in them.

Depending on your level of paranoia. You might worry about someone breaking in and stealing the supplies you are counting on. Here the secret is camouflage. Go to an auction or second hand furniture store. Purchase the cheapest ugliest set of sofas and chairs you can find. Try thinking along the lines of something that your in-laws might get you. The idea is to get something no one in his or her right mind would steal. Now tuck your supplies in the cushions, up in the springs, in the back ETC. It is amazing how much stuff can actually hidden this way. Behind and under the drawers of a filing cabinet, dresser, whatever. Do not store anything important in anywhere a person would normally look. The idea is to use something that would be worthless to steal then hide things inside. Sure the stuff can be found it just that unless the thief has a reason it is most likely that they will not look