ok so physical exercise seems good. i would maybe start working in more MENTAL exercise. short training sessions as recommended above, maybe make eating time brain time (use kibble for the training sessions, play hide and seek or other games, train a new command, use interactive toys for feeding like kongs or kong wobbler or tug a jug or whatnot).
I would crate when no one is around, but first start taking it out again and get him re-used to it. He will need more supervision when people around by managing where he can go. use baby gates or other, close doors. Have someone keep an eye on him. Sounds like with so many people in the house it's hard to keep track of him.