I wish I could remember how to solve it. The old BBS had so much info we sometimes need that can't be found anymore. I do know moving the mailbox and or trashcans sometimes causes portal problems and sometimes putting those closer to the road or back where they belong can help fix a portal that has gone haywire. I'll try to help find a better answer since I do have a lot of cc and know that one mailbox causes all sorts of problems and so does that trashcan, if anyone has anything installed later than BV.
ETA: This thread is talking about when Sims got stuck at vacation and can't leave at the hotel. Their problem seems to the be the taxi that picks up the Sims on vacation. They used a teleport shrub instead of calling to leave (link to shrub in the thread) Maybe that can help you before they leave the vacation area, to get them home without repeating trying to go back on vacation. But make a backup of your game before trying this.
http://modthesims.info/t/576630