When I checked the vinyl today I discovered it was very loosely adhered. So, I decided to try a little experiment by pulling the upper half down and using contact cement on it, same process as used with laminate application. Apply, let dry and then roll out. I used the larger laminate roller on most areas and a small, wooden wallpaper roller on any stubborn areas. Worked great with the exception of the fold crease. Improved but still visible. The spray adhesive performed better in my test sample, go figure.
For the other two walls, I plan to cut out the fold crease, overlap the edges and add trim if needed. Another hurdle cleared. Thanks to all for your suggestions.
In addition to wrestling with the vinyl today, I got the remaining flooring section cut and tarred. I used a paint roller previously but today I double-gloved, grabbed handfuls of goo and smeared it on by hand. Worked much better and very little mess. Cleanup: four gloves in the trash can.
I also cut the aft bulkhead, applied more laminate to the wheel wells and installed my first section of ceiling. Next up, screw down the last of the flooring section, apply vinyl to aft bulkhead, construct divider wall and apply vinyl to it, build desk area and upper cabinet, build bathroom vanity and upper cabinet and,,, the list seems endless but is getting shorter day by day. Enjoying most every minute of it!