you could use "Dynamic Clearance" with the Move Component command. When you are over a component in the graphics area you can click the RMB and you should see the "Move..." command:
However as far as I remember "Move..." is not turned on in the default RMB menu and you might want to turn it on so that you get this command whenever you use the RMB over an assembly. If you do not want to customize your RMB menu you can manually expand it and you should find the command from there.
After you have selected "Move..." you should see the Move Component PM and you can activate "Dynamic Clearance", select the two components you are interested in and you should get a dynamic dimension on screen that automatically updates whenever you move one of the components:
You can also specify a minimum distance the manual movement should stop.
This is not exactly what you are looking for but it is at least an easier way to get the distance between two components.
SOLIDWORKS Product Definition Team
Thanks for the response. I hadn't there was a dynamic clearance in the move tools.
Another thought I had was whether motion studies have sensors like analysis does. If something like that exists, I can do 1 full rotation and see the minimum value.