Welcome to iRV2.com, tbottle!
This is do-able, but you will lose the load control capability the ECC provides. Maybe the guide starting on p9 of this manual
will be able to help you troubleshoot and fix the problem instead.
To find out how other people have done it, search for "hunter rv thermostat replacement", there are several articles on the 'net from people who have done the conversion from analog to digital thermostats. Of course, you will have to relocate the wiring and put a t-stat for the second A/C and heater into the area of the RV that they feed into.