There's tmate: a tmux fork wich allow instant pairing without the hassle of ssh'in into the other computer and running a shared tmux. You can instant-run with the online service or install and use your own tmate server (BSD-licensed).

https://tmate.io/

I vpn into my home network when working from coffee shops etc and ssh into my workstation. It does require a semi descent connection but mosh helps mitigate a lot of issues with ssh and latency. Works pretty well and gives me descent battery life to boot since compilation/tests now run on the remote box.

I've also done it through a cheap digital ocean instance but compilation speeds are much worse and running tests takes longer, but it's a bit easier to set up and try out I guess.

mosh with ssh, very fast, resilient and excellent when roaming networks. Even the worst train network connections work decently with mosh.

https://mosh.org/

I'd imagine it'd be pretty easy to do that with tmate, but I'm only ever sharing sessions on a LAN or VPN so I could be wrong.

Of course, you can always ssh in to a shared account.

ssh