Here's the thread about packing for a tour- there are some great ideas for packing in general that might be helpful in your situation:
http://smnetwork.org/forum/stage-management-plays-musicals/tours-tips-for-packing/ To avoid lugging a lot of books around, I think an iPad, Kindle, or other e-reader is a great idea. Or, if there is a public library system nearby, I usually get a library card once I'm there.
Will you have access to a kitchen? If so I would make a list of basic kitchen items to take, including a chef's knife, saucepan, and frying pan. Even if there isn't a kitchen, bringing some cups, plates, and silverware might be a good idea.
I spent a few months out of town twice last year- the first time I didn't bring very much, and the second time I brought a TV, my Nintendo Wii, my houseplants, and a bunch of other things to make the stay more "home-y". The downside to bringing more stuff was (of course) that you have to pack it all up when you leave. If you don't have a lot of downtime, it's definitely not worth it to pack the "extras". But, it's nice to have something to do with time off- read, knit, go running. Pack what you need to do something for yourself every once in a while.
An umbrella.
I second Loebtmc's "shoes" suggestion.
An alarm clock.