Are you planning to follow the book as written or completely re-work them? If you follow the book, the girls generally don't like them. I've heard that the Get Moving journey is especially boring. So, I would tend toward Amuse or Agent of Change.
My girls refuse to do a journey. I've suggested it and asked them to vote on it about 5 times in the last 12 mos. I've described the options and explained that we could do it in 2 mtgs. plus the Take Action Project. I've explained how some of the service projects we already do could be slightly tweaked to satisfy the TAP. They DO NOT want to do a journey. That said, if I could ever convince them to do a journey, I would follow the 2-mtg + TAP formula that this council has created:
http://www.girlscoutsrv.org/volunteers/troop-leaders/junior-leaders/junior-planning-guide/
Good luck