I would recommend a Windows machine to run the software (doesn't work too well in virtualized environments as it needs direct access to the GPU hardware). You could install the Prime software on any other windows PC, but you would need to physically move the XPression dongle between the machines to allow the software to run.
Alternatively you could look at purchasing a copy of XPression designer which is a lower cost offline version of XPression for designing your graphics which you would then copy over to the production machine in the truck.
#XPression