Quite a few years ago, someone bought a Pantera with the heater disconnected. When the new owner hooked up the hoses, it was found that some of the screws that hold the console down had been drilled into the heater pipe instead of into the floor. Big leak! The consensus at that time was to CUT the mild steel OEM pipe for easier removal & make a permanent two-piece replacement made of copper or ss. And be really careful in redrilling the console hold-down screws!
At most, you'll need to remove both seats so as to get at the console hold-down screws, both halves of the console, the rear upholstering panel & access door, and maybe the heater controls in the dash. But the powertrain can stay. And remember, to better route the heater hoses, use copper sweat-solder 90 degree fittings instead of wasting time trying to find molded 90 degree hoses, Which are usually weak spots anyway.