First, I’m working on the voucher question for you. I’ve got a friend of mine whose friends with several Amtrak conductors checking that one out. I only asked him late last night about it, so it may be another day or two before I’ll know.

Now for a few other thoughts and suggestions on your trip. First, as soon as the conductor comes to take your ticket, mention that you are interested in an upgrade. Don’t badger them, but also don’t let them shirk their duties either. Give them enough time to collect everyone’s tickets, but don’t give them hours either.

They do have to call space control, both for the price and to ensure that some ticket agent down the line doesn’t sell the room to a passenger boarding there. But they are required to upgrade you if the room is available and the price is agreeable. You can confirm that room(s) are still available by pretending to ask for an upgrade at the station from a ticket agent, before you leave. That will help to prevent a lazy conductor from telling you that none are available. If you’ve got a cell phone, you can even call Amtrak’s 800 number while onboard to see if rooms are still available further down the line.

Now, in terms of cost, if you decide to use points that’s fine. But as Paul pointed out, you might also want to consider the rail-sale specials too. That said, regardless of which way of paying for your base fare you choose, let me recommend the following.

While it might seem a bit out of the way to go to Chicago via Washington DC, you might want to consider that idea. Overall the ride isn’t that much longer than taking the Lake Shore. The Capitol however uses Superliner cars and sleepers, which have a much higher capacity than the single level Amfleet & Viewliner equipment used on the Lake Shore Limited. This higher passenger capacity often makes this train cheaper, especially when it comes to upgrading to a sleeper. It’s also less likely to sell out the sleepers, since there are more, increasing the chances of an upgrade.

If you are riding on points, then this extra connection won’t matter at all. If you are paying via a rail-sale, then it could cost you extra.

The routes that you’ll be riding don’t vary their prices by day or week only by % of seats/bedrooms sold. Upgrading onboard to a sleeper under current Amtrak policy, will always get you the cheapest price for that room, assuming that one is still available. That’s the price that Amtrak first offered when the train first went on sale 364 days before its departure and can often be a couple of hundred bucks less than what's being offered right now on the website.