The only problem with going into vacation mode is your customer won't be able to find your shop in search. Vacay mode removes you from the general shop search, and obviously all your items get pulled, as well.
When we leave, I just put an announcement up as to when items will be shipping out - I don't even say I'm going out of town, I just say items purchased "between this day and that" will be shipped on "date". Of course, we're rarely gone longer than just a few days, so it's really up to you.