If you have points at Holiday Inn, (Intercontinental) you can, as The_Traveler pointed out in another thread, turn 10,000 Priority Club Points into 2,000 Continental Miles, then once you have at least 5,000 CO miles, convert those to Amtrak at a 1:1 ratio, a little better than Hilton's 10,000:1,500, but I agree with Alan, the "bath" you take on the conversion isn't normally worth it, unless you have "a random 10K or so" with a hotel that you aren't going to use, or aren't enuff for a free nite.......
CASE IN POINT: My wife has 10,335 miles with Virgin America. She most likely will never, (or at least for the foreseable future) not fly Virgin again. But I opened a HiltonHonors account in her name. We will then transfer those 10,335 Virgin miles into HiltonHonors, and then transfer them out of Hiltonhonors into her AGR account......and maybe if needed, then she will SHARE those points into my AGR account, for a small fee.