We did this in our last trailer and really liked it so we did it again, replacing our Coleman Mach analog unit in our new-to-use Rockwood 2701SS.
The Hunter 42999B we used last time doesn't seem to be available anymore so we used the Supco 45034, which is very similar. Last time I added a toggle switch for AC fan high-low; we rarely used it so this time I just clipped and insulated the low signal wire and connected the high.
A few photos...
The wiring diagram:
Overcast outside and dark in the trailer with all the power off, so...
Clipping the wires off the old thermostat:
New thermostat back plate installed and wired:
A nice fit. All systems tested and working properly. And now we have Celsius (a benefit I don't expect Americans or older Canadians would appreciate).
Full write up at Mods - Digital thermostat