There are a lot of journals on CGOAB written by tourists using trailers, mostly the BoB trailer. I have not used a trailer, but from reading the journals, there seem to be two main reasons for using them: 1) extra carrying capacity, and 2) with a light bike that is not set up to carry panniers. In your case, the 520 is an ideal bike for using panniers. A trailer will add weight, and the 520 is already a fairly heavy bike. Like other posters, I question the need for a repair stand on a tour.

You also mentioned MRE's. Are you referring to military issue MRE's? If so, they are very heavy, contain an awful lot of disposable packaging, and except for the candy bars, taste pretty bad. If you need to stash an emergency meal, I would recommend one of many freeze dried options available at any sporting goods store, or Walmart. Most of them can be prepared and eaten right out of the packaging. And you can buy a Snickers bar when you get to a convenient store.