what can i do to fix my interior?

Okay so i was trying to start my interior over from scratch and i was deleting rooms but once deleted some didnt take the stuff inside with them and now its all just sitting outside and i cant put new rooms up to try and go in and delete each infividually becasue the stuff that didnt get deleted is blocking any new rooms from being built, so now my interior is a royal mess! there are toys scattered areas with no actual rooms and rooms i cant access because they are no longer connected

is there any way i can delete the whole thin and jus start over without messing with my toybox saves? i dont wanna lose that stuff i could make a new interior but its saving it with my other toybox saves it looks like, and then i would have the new one without the lobby and the second one with a lobby but in shambles id rather only have one is there a way to start over or make the new one the only interior?