Let me get this straight. If the fridge doesn't work it will make a great place for boxed and canned food storage. A cooler can take it's place for under $100. Propane bottle expiration can be resolved by using one of the exchange services like at Circle K, Lowes the local grocery store etc. IF there is a roof leak that could probably be fixed with the roll on coatings. The only issue I see is the tires and bearings, of which this trailer probably only has two. How much can that cost in the big scheme of things? All in all, for your stated purpose, this seems to be an extremely good deal.
RichH