I dont have a shop, but want to let people that may buy my BIN items i will not be able to post for a few days.
Without a shop you would have to add the info to your listings description yourself,BUT, as many buyers dont read,its best to just not list while your away if you dont have internet access as your account could suffer.
Not possible and it's not a good idea to have BIn items running whilst you're away.
Buyers will expect items to be delivered asap and wont take kindly to having to wait - harsh I know but it is how it is.
Better ideally to get your listings to end around 2 weeks before you go away in case of any problems arising that you need to be around for.