You have 60 days to redeem the points. The Transfer option may not be available if you are no longer a Prestige or Premier cardholder. Did you verify this? (Asking because I vaguely recall one anecdotal report.)
Assuming that you can transfer, I would transfer to VS:
ThankYou (USA) 30% bonus on transfers to Virgin Atlantic (VS) until June 22, 2019
Limited options isn't a big constraint for this small amount.
Yes, I have Premier card (for now; planning to cancel as well).... another 55k-57k over there.
Lifemiles has a 25% on Citi transfers as well. And, my slight preference would be to lean towards UA partner (given there will be more options from ORD). Which would be better between Krisflyer and LM (for purposes of domestic redemption only)?