Thanks for the suggestion.  It's worth a try...

Unless you really need menus, you can fit 5 times as much material on a thumb drive with Handbrake than by copying dvd folders over.

You can't always fit two standard dvds on an 8GB flash, but you can fit 5 or 6 h264 Handbrake conversions from dvds, and the quality is indistinguishable. h265 is going to be even better, but the rendering times are still daunting.

Something to consider any time portability is a requirement.If you must put a dvd on storage or flash media, keep the .vob size to 1 or 2 GB chunks. A 4+ GB single .vob will not work.

Several years ago John Meyer provided excellent instructions on how to create an .mp4 file with chapters, using Handbrake and a shareware utility called Drax. Following his instructions I had no problem placing projects onto a flash drive. You should be able to locate his postings in the Sony Vegas Forum archive. Also keep in mind that flash drives are typically formatted as FAT32, limiting file size. The file system can be converted easily by using the "convert" command on the prompt line: convert D: /fs:ntfs  Note that there is a space between the D: and the slash. "D" of course should be whatever drive the flash media is in.

Found the link here on the forum: https://www.vegascreativesoftware.info/us/forum/adding-chapters-to-mp4--71733/ It provides complete details on how to do chapters on the flash drive.

Right, the chapter points from drax and mp4box will work in most players - it is menu pages that are not supported in mp4 and m4v. Oh, those chapter points worked great in Handbrake, last time I tried.

The mkv standard is written to eventually support menus - just no one is much interested in working on it.