Hi Stan,
I suppose that the physical calculations, it's for all the rigid objects of the scene… Then, why are you not convert them into keyframes ?
I automatically do that for each object, and sometimes, I convert into NLA clips or save this part of the scene in my objects library.
In this manner, I can work on another element of the scene without having all to recompute.
Saving in the library works for soft body too, but we cannot convert these simulations into keyframes.