What I've used in the past when renting to run Ethernet up a flight of stairs and down a hallway was a single cable "wiremold" that ran along the top of the floor trim that made it almost unnoticeable. Another time I also used wiremold, but didn't want to spend a bunch of money so I just cut it into 6" strips and only applied them where the cable started to become not straight (ish). Also, some wiremolds have a weak peel and stick adhesive on them, that shouldn't damage paint when removed.