Basically swap what program is in the foreground on one screen at the same point you'd otherwise look at a different screen. Alt tab or whatever the keyboard shortcut is to see the docs, then again to go back to the editor.

It's slower and it's worse, but I write a fair amount of code on a laptop in hotel rooms and it works well enough. Most annoying things are probably the loss of scrolling test output on the second screen and difficulty doing multiway diff compares.

Super ultra wide