Tom,
The heater on my 67 Tradewind is easy to remove. First remove the
center upright board of the cabinet. This is in front of the heater.
The heater is in its own sheet metal cabinet. Remove screws around the
front parameter. Disconnect the gas line and the wiring connection to
the thermostat. Disconnect the 12vdc connection and mark which wire to
the heater is positive (black wire in the Tradewind). If you later
reverse these leads the fan will run backward. At this point the heater
should slide out the front. Make sure the intake and exhaust pipes
align with the holes in the wall when you replace the heater.
This all assumes that the 69 and 67 are similar.
Best Regards,
Jim