One thing to wonder about is whether Amtrak would change their program significantly without any notice.

But you don't have to wonder-they've did it twice in he past. The first time they limited the number of miles that you can transfer in a year to 25k, which restriction may still be in effect. The second time was to eliminate certain partners to which miles could be transferred.

I don't know when Amtrak will again change its program without advance notice, but I plan my activities on the assumption that, based on the past, they may well do so.