It depends how long your going away. The only current drain on the car will be for the immobiliser/alarm and the clock. Provided your battery is ok should'nt think you would have any problems.
Went away for 5 weeks last winter came back and my 15yr old Mondeo started first time. It was parked in the open.
If you do disconnect your battery, don't forget your radio code, otherwise I can anticipate your first question on here when you return :)
Reading your question again are you saying the car will be in a garage? If so, do not think you will have a problem unless your going away for a real long time.
Enjoy your holiday! Do you need anyone to carry your bags?