Feeding a large snake in an enclosure with sliding doors isn't at all difficult, we have several adult retics in 8' Boamasters with sliding doors. Use really long tongs, don't stand directly in front of the opening, and open the door on the side that the snake's head isn't.
Same goes for handling except put the hook in and tap/rub the snake a few times. You should see it relax after it investigates the hook, and then you can put your hand in and pick it up, or use the hook to gently encourage it to move if it's cage defensive. In the latter case I'll open both doors (move each to the middle) and usually the snake will try to come out the side that the hook isn't. At that point it's easy enough to let it crawl out onto you under its own power instead of being picked up. They seem less stressed that way.