The vacation is a tough decision. Personally, I wouldn't do it. Her relationship with the kids continues to suffer and this is more of the same, running from them, to the neighbors, and freedom. The only difference is she wants to drag you along for the ride. I think she would feel completely satisfied with life if you were going through this MLC with her....becoming partying kids again. I wouldn't let her drag me into her personal hell.
I'd put her off in some way. Choices are: 1) "I don't think the timing is right for us." 2) "I would prefer if it was just us." 3) "I would prefer a vacation that includes the kids. They need this as badly as we do."
Just some thoughts.
As you write this stuff I can't quite understand it...mainly how she won't leave the house. And it's always that..."I can't leave the house.", not, "I can't leave you or the kids." Is that what she loves, the house? If you and the kids went away for awhile, would it bother her as long as she was at home? Is her preference for you to move away and leave her the home? It really bothers me that there seems to be something there that she can't leave....is it truly the neighbors? Do they have something else going on? I've seen that the seemingly "irrational" jealousy that spouses get in this kind of circumstance (ie "friends" or "just internet acquaintances") doesn't turn out to be unfounded. These two are fulfilling some emotional need that she has...which means you aren't. If you went on vacation, they'd still be there filling that need. She needs to learn to actually live without them.
You cannot be lonely if you like the person you're alone with. Dr. Wayne Dyer