I also share(d) your concern. Diego was 7 mos old when neutered on Thursday and I took Friday off. It was absolutely necessary for him to have the e-collar on because he wanted to mess with his incision. At first he wore the cone only when I wasn't home, but he actually licked it open in seconds when it was off just before getting into bed. In fact, I posted that fiasco on a post last year :o!
He was fine with having the e-collar on while in his crate. At the time I was 15 min away and was able to go home during lunch. In fact, he's using it again right now so he won't bother his stitches on his head. I don't like the idea either, but the alternative can be very dangerous if he were to bump into or get into anything. He can move around without any problem.
Fourteen days is a long time, but I think by day 5, I allowed him to run for 5-10 min max. He did okay. These boxers are pretty resilient, both physically and in character

! Best of luck...
Lisa