I have a 4 tier topsy turvy cake to deliver in a couple of weeks. The caterers won't take responsibility for signing for it so the mom is going to meet me at the venue and sign.  I have to have it there by noon. because she can't come any later because of the wedding. The kicker is that the venue will not keep it in the fridge for them so it has to be in the air conditioned reception room from delivery on. I am making a dense cake, cooked filling which I will thicken more than usual and I will cover it with dark chocolate ganach under the fondant. Any other suggestions?

It will be fine as long as you don't use perishable ingredients

I would be sure that the design you're using only gives the illusion of a topsy-turvy cake is actually balanced perfectly, and that the cake table is 100% level and sturdy.

If it's going to be more than 8 hours before service, I would transport it cold.