There is absoutely nothing worse then a group of women not on the same page.  If you go camping...make sure they all like to camp and can accomodate themselves.  If you hike...the right shoes are important when you do mileage.   If you prefer the soft sports, ie spa...make sure they all can afford it.  The planning is important and everyone should be on equal footing and have a little common sense.   Then enjoy your time away from family, work and the daily grind.