I am STILL able to see the following flights available:

21MAY
BOS-SFO 6:00am UA 171
SFO-SEA 10:42am UA 322

01JUN
SEA-ORD 11:45pm UA 754
ORD-BOS 9:25am UA 528 (next day)

The only bad thing is SFO-SEA is in Economy, but you are welcome to waitlist for F since this is an all-UA award.

I found all the above by plugging in May 21 - Jun 1, two First Saver Award seats on united.com.