Amtrak AutoTrain discount codes

we got an exchange _in_ Disney (Saratoga Springs) for January, and have decided to try the autotrain to get there (since the kids love trains, also.)

right now, there's the regular deal of kids are half price, but I also saw an expired discount code for kids riding free on the autotrain for travel though December. (we couldn't have used it, of course.)

anyone have a feel for the frequency of Amtrak offering discount codes for the AutoTrain? Is there likely to a similar one offered for January travel?

thanks.

I'm thinking of taking the autotrain as well.

Two questions:

1. How early should we book for an April 27 trip?
2. Where do I find discount codes?

Thanks,
Charles