Sensors, I tried 5m USB 3.0 active extension cables, tracking kept dropping every second. Tried 3m USB 2.0 instead and that worked fine. Both go throught a USB 3.0 hub then another USB 3.0 extension cable so it's easier for me to unplug both sensors from the front of my PC easily.
As for HMD, 2m HDMI extension with a $2 HDMI repeater and 2m USB 3.0 extension cables work fine. The repeater is essential, you'll get audio but no video without it.