I've never removed a rear heater, but it should be pretty basic. Just follow the 2 heater hoses back to the source and remove, then place a shorter hose that travels between the 2 empty nipples. You could always just put a barbed coupler in place of the absent heater core, but having all that extra hose between that location and the engine sort of defeats the quest for lean and uncluttered.

Perhaps I missed that section in the FSM, but as I recall there seems to be a lack of information regarding the heater cores and their associated plumbing. Good luck and have fun! Tim