Originally Posted by jtintx
I was told that it would cost $500 to $600 and that the wiring would need to be replaced
Sounds crazy. Here is a link to a thread on upgrading to a 'household' digital thermostat. Has some nice pictures to go with the explaination. The wiring is not an exact match. The trailer has a 2 speed fan, and the replacement is only setup for one speed, so the solution in that case was to only wire up the high setting.
Hunter Thermostat Install
Or for a few extra bucks (not hundreds) you get the Coleman Mach digital version. It's an exact replacement as far as the wiring, and I believe the mounting screw locations, so truly a do-it-yourself job. It's digital, but not programable. Not sure if that matters to you...