Pulled the core out this weekend (about 2 hrs or work) measured the unit at 17" long, 6" wide, 2" thick. Connections come straight out one end and attach to hose then control valve.
My coach is #10628 and has the specialty climate systems (victory climate systems) hvac kit number HC230.
Country Coach is in operation again but not manufacturing yet and therefore they don't have the part. VCS referred me to Monaco and for $250+ and shipping I can have a new core. I've resigned to shop around and find replacement.
If anyone has a lead on a heater core near the 17" length/6" width please respond.