Congrats on the new toy. we may all be soon using google credit and consumed by the google cloud. no more ownership just corporate commodity and access.
That aside it looks like the c720 does have a legacy boot option, here is a link to install arch that would be very similar in process.https://wiki.archlinux.org/index.php/Acer_C720_Chromebook
A full install to usb or the unit would allow you to add programs. Vector does not offer persistent storage so live from usb means no saved settings. frequent writes to usb shortens the life of the stick to my understanding but if storage is clouded then it would just be the install of os and additional apps. and the additional ports offer local storage aswell
on a quick scan it may mean losing all your data to get into the developer mode to enable the seabios. but a temporary situation I would hope. sounds like fun
Do post how it goes if you will