Sincere apologies if this has already been answered elshewhere. Pls fell free to delete this post and redirect me.

I am a hbbby baker. My best friend has asked me to do her wedding cake. It will be a two tier, chocolated mud cake with cream cheese filling. I use ready made chocolate icing to crumb coat ( I work full and time have two toddlers in the house. It's easier and cheaper to use ready frosting than to make ganache). My question is this. In Greece the weather is extremely hot at the moment. The venue is about a 30min drive from my house. (I don't have time to fondant cover the cakes and stack, on the day of the wedding, as I am working). If I refrigerate the cake after its done (crumb coated and fondant covered) and take it out to take to the venue, will the heat tear up my fondant? How can I prevent it from sweating and coming apart? I will be using the car's ac on the way to the venue, but will that be enough?? I am so stressed, I feel sick :(

First of all, take a deep breath and relax.  Don't make yourself sick, you have too much to do. : )  My first question would be, is the reception going to be inside or outside?  Is there refrigeration available for the cake until the reception?

If the only heat you're concerned about is during transport, you'll be ok. You can refrigerate fondant cakes, but I would only do it if it's in a box wrapped in plastic wrap.  That way, when you take it out any condensation will be on the outer wrapping and not the cake itself. Transporting in a cool car won't hurt it.

If the cake is going to be outside or in a warm venue, then I would re-think the whole cream cheese filling idea.  Unless you use a stable recipe,  it can only be out of the refrigerator for about 4 hours so you need to take that into consideration.

The reception will be outside :( but the venue assured me they have a fridge to keep the cake in, until they bring it out to cut. I thought (and agreed with the bride) that I will be using a big cardboard box (not a cake box) to transport the cake. Regarding the filling, it is - I would call it - a greek version of the one I find on the net, which contains no butter. Just cream cheese, powdered sugar and cookies. I am thinking of adding some crisco to it, to prevent it from "melting"... The cake will taken out of the fridge (at the venue) maybe 5-10 minutes before it is served... So, if I put in it in a cardboard box, add crisco to the filling and use my ac while transporting, do you think it will be ok? THANK YOU SOOO MUCH FOR YOUR HELP!!

It sounds like the refrigeration issue with the cream cheese filling is covered.  If they're going to serve it immediately, your filling should be fine without the Crisco in it.  My only concern would be the condensation on the fondant when it's taken out to be served since they probably won't keep it in the box.  There will be condensation on the fondant, but as long as nobody swipes a finger across it, it should dry by itself without a problem.

I finished the cake last night (been up fro 26 hours :( ) the box is too big for my fridge, so I have just put the cake in and will transfer it to the box as soon as I take it out. Have spoken to the metr d' and asked him to keep in in his fridge up until the minute they are to cut it. Fingers crossed that it will be ok, at least for the photos!! Thank you again so very very much for your help! I will let you know how it went! All the best!

You should keep it in the box to prevent moisture getting to your cake. If you keep it in the fridge uncovered it will start sweating quite a bit once removed - no matter if you put it in a box later. And it might absorb unwanted smell from your fridge as well.