Set up a headless Raspberry Pi and connect by SSH and VNC. To connect the two devices use a USB cable.

Alternatives:

• connect them both to a router using Ethernet/wifi.
• use a very small PC in headless mode so you can run x86_64 executables.
• access a shared git repository on the cloud using local clones on both devices to share files

This may be less sexy but it is solid and reliable.