Thanks for all the info. I know for sure we want to see Amsterdam, Berlin. We could pass on the Mercedes and Porche museums as I am not really a fan of either car maker (just a car fan in general) and my buddy is not a car guy. So by eliminating that it opens up free time. We are flying into Frankfurt as it appears to be the closest airport to my buddies camp. He is going to come up that morning and meet us, we have looked up train info and it says its a 3hr 42min ride to Amsterdam and theres a train leaving right around 1 1/2hrs after we land which should allow us enough time to get off the plane, get our backpacks and go.
We did look at the castle that inspired Disney and that looks pretty cool. I found Hostels for $9 a person each night, and if they are the same as the pics shown then they aren't bad. We still have 6 months to really figure everything out before buying plane tickets, setting up reservations and getting train passes taken care of.
We are planning on getting one of my friends army buddies to let us either borrow a car a few days or just go with us. They know a few Germans as well which should help with the translation stuff, and could help if they know quicker routes. I will check on flights from Frankfurt to Amsterdam and then from Amsterdam to the US.