I agree with you that if you have to work with multiple systems where you do not have control over installing packages, you might be better off to use pre-insta

I agree with you that if you have to work with multiple systems where you do not have control over installing packages, you might be better off to use pre-installed screen and vi with default configs so you can get right to work. But if you have your own workstation and do most of the work with this workstation, tmux + customized configs might be a viable option. It just depends how good your muscle memory will keep up. :)