A FlyerTalk Posting Legend
Join Date: Sep 2009
Location: Minneapolis: DL DM charter 2.3MM
Programs: A3*Gold, SPG Plat, HyattDiamond, MarriottPP, LHW exAccess, ICI, Raffles Amb, NW PE MM, TWA Gold MM
Posts: 100,368
If you have elite status that gets you free changes to award tickets (for example, PM and DM on DL), when you book the outbound, just stick in some placeholder return flight, perhaps on the following day or to a destination in the same region you wish to travel. If you have lots of miles, you don't even need to bother looking for low award availability.
Then when flights open for booking on your desired return date, change the ticket for free and have any excess miles returned to you and any excess fees credited to your original credit card.
Some people even consider it worthwhile to pay the change fees, currently $150 per ticket, to grab the outbound space they want when it becomes available.
However, airline FF programs now seem less likely to necessarily release award seats at 330 days or whatever. At one point, people believed that all award seats were released when the schedule opened. Now it's all based on yield management and seats can be released or repriced in miles at any time.