What tools should I use for hand carving and whittling?
Have you considered one of the portable workbenches such as the Workmate?





They fold to a pretty small package and come in a variety of sizes and prices.

Black and Decker used to make several Workmate vises in a benchtop and toolbox version such as these 





They appear to be discontinued. I found mine at yard sales, but they show up online occasionally.

If one of these suits, you may be able to continue to use your preferred tools.