Without knowing it any better myselve, and without googling to much.. I would try and mount the host OS (the one on the macine) /boot/ partition into /boot/ of the guest OS (the one on the stick) and than edit the guest OS /etc/grub.cfg to include the nomodeset and than run the grub update.
Can't say if that could work, but worth a try I guess
Okay, so after reinstalling the system, and deciding to have a go at trying the keys again, the escape key worked! Thank you both for your advice. If nothing else, this has been an informative, and rather fun play with trying to troubleshoot Ubuntu. :)
You are very welcome. And welcome to the amazing world of linux. It may not be easy, it may be frustrating at times, but after all you learn!
And most of the time you can fix stuff with hard work, and not just waiting for a fix to show up at some day in the futur like the other Operating systems