You don’t need to follow the laptop rules for the placement of the display. I think a small screen should be placed before the keyboard.
A startup idea would be to create a small screen Linux portable keyboard. The difference from a laptop is that the small screen is placed infront of keyboard and no large display is needed.
Such a portable keyboard computer with display could be made much smaller than a regular laptop and still have good interaction performance. For coding and writing.
So the tip is to get an external mini keyboard for the phone and connect trough ssh or vnc to your raspberry pi and program a little while traveling.
Be sure to change password for user pi and possibly add two factor authentication by installing libpam-google-authenticator for ssh