Go for the hard white Italian cheeses. Last year I found some in my grocer's deli section that was individually wrapped - it said "keep refrigerated" but I figured what the heck. Put it, a salami, a sleeve of wheat crackers, and a couple cans of wine into a resupply bucket that was mailed to Muir Trail Ranch on the JMT; we're talking almost a month, including several days with the bucket sitting in a shed in the sun at MTR. I can tell you how delicious it all was - including the cheese - as we noshed riverside. Lots of jealous looks from fellow hikers!