If it were me, I'd reheat the gravy in the microwave. That way you don't have to worry about scorching the bottom. If your nuke has a lower setting, use that if you wish.
I just set the timer for about 8 minutes on high. When the timer goes off, I give it a stir and reset it. If you are busy doing something else, it won't hurt for the sauce to set a bit before you reset. Just keep doing that every once in a while, and your sauce will be slow cooked without the mess. You can do this for as long as you wish, but your sauce will be ready in an hour or so, and be very good!
By the way, I use a large pasta bowl to reheat the sauce, and cover it loosely with a piece of waxed paper to keep it from popping and making a mess in the nuke.
Your meal sounds lovely! If you have any leftover, you can send some my way!