In the west metro you'll pay about $10/foot minimum for indoor storage for the season, usually mid-October to mid-April. Some charge a flat fee for the same timeframe. We're west metro and pay $320 for 6 months, size not a consideration (thanfully). Look for storage with a concrete floor and one that hasn't had feed stored for the summer. Mice will definitely want to share your spot.
Lots of farms out this direction are looking for folks needing storage. Craigslist is a good place to start. We've always had good luck at the fairgrounds too. Try to avoid the animal barns if possible, again because they attract mice. They will let you store your items year-round but will notify you when you need to remove your items for the fair, usually for two weeks max.
In this area, they pack them in like sardines indoors. Can't even squeeze a 10-year-old between them. So don't plan any post season trips.
Winter sure takes a toll on campers. A couple hundred bucks is a good investment to keep them out of the elements.
