Yeah, I have been trying to figure that out. I can buy an “international license” from USAC, which allows me to race in UCI-sanctioned races but I couldn’t figure out if that meant UIC affiliated national federations as well. But there does seem to be a way to enter your foreign license in the registration forms for races in Germany, so that’s promising. My strategy for now is to race in the US until I go to Germany in August and then probably buy a couple of day licenses in the fall until I figure stuff out for next year. 
I’ll likely hit you up when I get there, anyway.
Thanks for all your help. And, @zwillis1, will definitely look at some races in Czech Republic, that sounds awesome!