I ran another test on this and had a few updates
- The Portable page addresses a "portable mode migration" (https://code.visualstudio.com/docs/editor/portable), which is a very unusual thing to find, but I'm very happy to see. After all, if your local copy runs the way you want it to, why jump through all the necessary hoops again to get the portable version running the same?
- dotNET developers may get prompted to install an "dotNET Core" IDE that isn't even remotely portable, but some csharp tools did save to the data\extensions folder at a unfriendly 300 megs. All told the process cost about a 1.1 gigs of space on my machine.