Kerry : not such a good idea to advertise that you are going to be away for 2 weeks! Open slather for not-so-nice people to visit your home and sample your property. :shock: You don't want to repeat Slatey's experience do you? :x
In any case, to answer your question, I think it largely depends on the type of snakes you keep. Some (such as olives) have no trouble with a bit of heat, but then again, it depends on how hot your snake room gets and what temperature the snake can handle. Does it usually stay cooler than the outside temp? I like both of African's suggestions, and Artie's suggestion of the waterbowl is a good one too.
When I went on holiday at Christmas, I left two drink containers and a large water bowl for them to soak in, in each enclosure. I saw how much Slatey's snakes like the waterbowl, so thought it was a good idea. I was very worried when I heard how hot it was in Sydney, but I got back to find them all ok, and one of them actually almost fully immersed in the water bowl (no, no mites thank God!).
Ideally, get someone you trust to check on them on hotter days. How do you handle hot days now? A couple of large drink bottles of water in the freezer can help, and if you can get a trusted friend to check on them, they can swap the bottles over, at the "cooler" end of the enclosure. I usually wrap the frozen water bottles in a towel so the snakes don't "stick" to the ice.
... just a few thoughts... hope it helps. :wink: