Hi MdC,
At this moment we have no free time to work on the portable implementation of Publii, as it can require bigger amount of work due potential issues with storing config etc.
But if you are able to use a Documents folder, please try the following path – I have tested it on my Windows 10 and it seems to be working:
1) Install Publii on your computer
2) Go to /Users/YOUR_USERNAME/AppData/Local/Programs/ and find Publii folder
3) Copy that folder to your pendrive
4) Rename the folder on pendrive to PubliiApp (to avoid conflict with Publii folder which is created by the App under Documents)
5) Copy PubliiApp folder from pendrive to the Documents directory on the destination computer
6) Open copied PubliiApp folder and run Publii.exe – it should works and should create Publii folder under Documents where all sites data and config will be stored.
Of course please double check if all necessary functionalities works as I have only made a short test to make sure if this way is possible 🙂