Thank you, thank you, thank you all so much for your responses!! Just getting around to try out all the valuable tips. Unified view was on, I checked that. I had no idea that I have to assign new texture/fill to an older model.Benson was absolutely right, the mesh model was an import from a 2012 project, thought it was originally on VW12, but anyway, applying new texture was all what it needed to work.
The "eliminating" process, and reducing the file to the model only, which I did before, helped at least with fewer crashes.
There were no objects far from the origin, so that it would show huge numbers on the ruler.
I am working my way through with walls and all other objects, very hopeful now to get it done.
bigx01