I agree, I would just vac seal, I have a chamber sealer I use most of the time but, Like Bentley has said freeze and then seal. Then just pop it in some boiling water to reheat. I would thing freezer bags would work also to boil to heat.
Growing up Woman used to buy some thing that were little sealed packs with the round Budig type slices of meat in gravy, then you just tossed them in a pot of boiling water. I am sure there were more flavors but I only remember chicken and turkey. Probably 5 or 6 thin slices of meat.
Have not had sausage gravy in a long time. It may be something that shows up for a Sunday morning breakfast soon.
She used to make the SOS but instead of using dried beef she used the cheaper chipped chopped ham, in a milk gravy.