Hi, I am making a 4 tier princess castle cake for a customer... the top will have turrets on it as well (on the 3rd tier) The tiers are 10",8",6",4" rounds. Can I dowel this cake and have the customer pick it up to bring to the party? Is that even possible? Or should I do it unassembled and bring it to her? Thanks so much for any advice- I have never done a 4 tier cake before in my life!

I think I'd deliver it and assemble it on site. Too many things can go wrong with a 4 tier cake. If they have to slam brakes you'll be the first one they call!

I agree, most people don't really know how to drive with a cake let alone a 4 tier one! Driving slowly to them could mean to never go over 40 miles per hour where as to a cake maker could mean never going over 25 (in town). And when it comes to the brakes, the cake maker never goes fast enough to need them much.
I live in a smaller town so I insist that I deliver most all cakes. I also don't charge anything for delivery because of this.