Yes, unfortunately, this is a known bug in World Adventures. There's no real solution for it. You just need to exit the game without saving and load it from a previous save. It may or may not happen to your again. There's no pattern to it.
Yes, the problem is the sheer number of issues that cause the transition to fail is so vast, that it is highly unlikely that EA will ever be able to correct all of them (or stop adding new ones with each Pack).
There are third-party solutions to this issue, if one is amiable to such things.
when the destination arrives there's no sims to control and parts of the interface are blue instead of green, which can be "fixed" by switching households for a moment in Edit Town before you travel (not a perfect solution because you lose promised wishes, but at least you can travel).
When you do this, you are resetting your sim's dreams and opportunities managers.
Those two systems are fraught with import/export related issues, and will quite often bounce the transition process. So resetting them clears any corruption related issues allowing you to travel.
Unfortunately, if your transition problem is not related to those two systems, then switching households will not resolve the problem... But it is certainly a reasonable first step to correct the error.
Did you bring a teen/child with you on your vacation? I read somewhere that if a teen's homework isn't at level 5 (homework complete? I'm not sure what level 5 homework means) then when you go on vacation the game tries to reconcile it and it can hang.
You are correct. EA Standard will force any traveling teenager up to Level 5 of the hidden Homework skill.
In doing so, there is a possibility of the game bouncing, and stopping the transition process.
This is normally only an issue with sims that were created as teenagers, since reaching level 5 is usually achieved during the child age-stage.
(edit: reset -> resetting)
