Hi, Steam Summer Getaway cards are from an earlier Summer Sale (2013, I believe). They work like a normal set of cards, and unlike more recent sales, the cards didn't disappear once the sale ended and the badge can still be crafted today.
I got enough cards for two sets that I'm willing to trade (although I don't have all the different cards at the moment), so feel free to contact me if you're interested.

Roger

10-4