Eastern Europe

How about flying? You could get a cheap flight with Ryanair from Frankfurt Hahn (which is a little bit out of the city I think) to Wroclaw and then train to Krakow.
Also look for WizzAir who have flights from Frankurt Hahn to Katowice which is closer to Krakow. Ryanair is usually cheaper but WizzAir flies closer to Krakow.
If you decide to take the train, you'll lose a whole day for sure even if you take the overnight train.
Maybe look for flights to Krakow, Berlin or Prague instead of Frankfurt? They might be more expensive but will save you time and if you consider the money you'll spend to actually get to Krakow, probably worth it.

thanks we are stuck with the trains and we must start in frankfurt so any ideas would help. We thought about going right from the airport to berlin and stay the night and next day the head out on a night train. We could also go down and go to Prague but we did Prague before. Any more help would be great

The night is a great way to save sightseeing time. I would make that my goal; to be on the train at night. We traveled that way with two teenaged girls and it worked out fairly well. We traveled for 2 weeks and spent 5 nights on the train. Any more than would of been too much. Berlin has plenty to see and do. You could spend at least two days there easy. Budapest is easy two days or more if you plan on soaking in the pools.

Thanks is a night train from Berlin to Krakow a viable option with a sleeper car. If we buy an eastern Eurpeon train pass it will cover the Eastern countries but not Germany. Do we buy a ticket in Germany at Berlin then they prorate it once we hit the border that we pay only for the sleeper supplement. It all sounds complicated so help would be appreciated. Last should we consider a night train from Krakow to Budapest. Thanks everyone