Bob, as long as the clock runs from batteries onboard the thermostat unit it should work just fine. I know when we got ours there were two Hunter models mentioned. One was programmable, the "setback" type of thermostat and the other wasn't. I wanted the programmable but Walmart was out of those and we were getting ready to leave on our 5-week fulltiming trial run and it was January, cold weather. I believe the wiring is identical to the non-programmable, if I recall.
Do you have the wiring info? If not, I think I might still have it on my laptop somewhere. It's not a real intuitive swap.
Found one of the wiring diagrams. This one is by fulltimedreamer and is a very good one. I hope he doesn't mind my posting this.
http://www.geocities.com/fulltimedre...m_upgrade.html
The reason you need one that is battery-run is that RV thermostat voltage is different than stick home thermostat voltage. The battery method allows using a stick home thermostat in an RV.