Illagone66
Get a tour of the Boneyard from the Pima air museum. They also have a D-21 but its in the resto compound.
If you go in there, though, you can walk right up to it.
There's another in Palmdale and another one in Paine field WA, mounted on the M-21. That's worth seeing!
They're actually D-21Bs. the -A model was launched from the M-21. The -B model from the B-52.