can someone tell me what is the longest you can leave a cake out at room temperature before freezing it for a week before decorating? i have to drive to get to a freezer and just wanna know if i let it sit about 18 hours before freezing is that too long? thanks so much!

Cakes can be fzn at any time. Since it will be out that long before fzing then consider it has 1 day less time to be eaten. Yes, it will still be very fresh - as long as it is wrapped up while it is waiting to be taken to the fzr
I consider a 'shelf life' of a cake to be 3-4 days. So your cake once finished will have 2-3 days to be eaten.

thanks so much that really helps alot!