been a few times as its about 45 mins down the road from me, well worth a visit.
theres a real random mix of planes trains and automobiles.
the 2 SSTs on the roof is rather impressive

yes, its a rather steep hike to the cabin on both of them.

also worth checking out is its sister museum in speyer (about 30 mins from Sinsheim).
they have a 747 a u boat and the aerotest model of the russian space shuttle.