I took the time today to take a few pictures of my storage system.
I used two cut down KR Multicase M3T foam trays and I cut out some pieces to make room for furniture and larger models. It barely holds everything but I managed to stuff the whole box and Kellar's Keep into it. Feldherr has a very nice custom tray for HeroQuest but it does not have room for expansions.
As you can see the door stands are a bit crammed together. This way the models will stay protected and always be at hand for a game. It will also take up less space than an extra box. I threw out the original insert.