can you set the "away" feature for a specific date range?

I don't believe you can set an end date for "away." If you have already updated your calendar you should be good; however, it won't stop people who don't pay attention from trying to contact you. When you are marked "away" your profile has a message that reads "this sitter is away and may not get back you you for a while" (or something like that).

Hope that helps.