Wow, that was surprisingly easy and the result is amazingly better ... almost too fast on my blownout mac!
James, thanks for the pointer to the Help section ... as a suggestion, you might want it to be easier to find from the home page ... Basically if you go to sketchfab.com, the "Help/FAQ" selection doesn't show up under Community until I selected a "Blog" entry and I had never looked back at Community to find it. Does that make sense?
For the C4D crowd, here's my feedback:
It worked well for this model because I do not have texture maps applied except to groundplane. Basically, in C4D you can pick a material, go to "Assign" and select all the objects using that material, Alt+G group them and then "Connect+Delete" to create a single mesh. Did that for each material and ended up with 4 meshes. I did have some objects with multiple "selection tagged" materials in a single object ... used the SplitToObjects plugin to splitout individual meshes.
Looking into how to do similar with a more complex texture mapped set of meshes ... atlas'ing the textures is the biggest issue, there used to be a plugin for this but the developer no longer supports it for current versions.