I'm looking to fly a round trip. There's a fare sale going on for certain days, but it requires a round trip purchase. The day I want to fly out is a excluded from the sale, but saver level awards are available. So I'd like to use miles 1 way for the outbound, and pay for a 1 way return. Unfortunately, if I book as two separate one way PNR's, then the fare for the return more than doubles, since it doesn't see it as a round trip.

Can anyone think of a clever way around this?

All I can think of is to book a RT for the return, with that leg as the outbound, and a return back to the same destination on some future date. Unfortunately, while I know I'll be returning to that city later this year, I don't yet know the exact dates...