Another option I just "discovered" to extend the expiration date is to use Avios for a hotel booking (this is an option in the Spend Avios section). Found a cheap option in LAS (2,450 per night) and have no plans to utilize it - just looking to have some account activity. Would cancel but there is a cash cancellation fee- no thanks.
Pros: No cash layout and no need to follow up to cancel
Cons: Lose the avios
For this particular account I don't care about losing 2,500 avios to save the rest. If for some reason this doesn't work I'll report back.