Certain facilities would be logical to retain; Landstuhl Regional Medical Center and the nearby Ramstein Air Base in SW Germany come first to mind. Centrally located in Western Europe, it was the principal stop-off & stabilization point for medical cases from Iraq & Afghanistan before returning to USofA.
I don’t think we need 30-40,000 troops there. We should still man the hospitals,communications centers and probably spec-ops. As far as regular military, they can be realigned into central America and the middle east.
Just for $hits and giggles, move an army division along with supporting air and naval units to Israel. Really drive the left up a wall.