I have a wedding cake to make for my step-daughter for next weekend.  It will be 4 tiers - 14,12, 10 & 8. The tiers are stacked. It will be covered with white fondant (my fondant technique is fair at best). It will have a modeling chocolate branch with leaves and berries trailing from the bottom layer to the cake topper.  Since the cake is stacked and the ornamentation is one continuous piece, I have no option that I know of other than to deliver the cake in one stacked piece.  I never worried about doing this with buttercream frosted cakes; but how do make sure that the fondant covered layers are secure on top of each other?  There must be a way to adhere them so they won't slide around. My other question is about adhering the modeling chocolate that will trail up the side of the cake.  If it's "hand warm" when I place it, will it just harden and ahere, or should I use something to make it stick.  This cake has to be driven to a pavillion on a bumpy dirt road. After 36 years of making cakes, this is one I'm actually nervous about.

Wow 36 years of cake making, amazing!  Well I'm not sure if I am any where near qualified to be giving you any advice, this will be my first post here, but I will do my best!  

I know there are lots of different techniques out there but I this is the technique that I was recently taught.  When stacking cakes it is best to make sure all layers are cold and as firm as possible.  Then dowel all your layers. Then spread a nice layer of THICK royal icing on top of the first layer, making sure to stay within an inch of the area of the next cake.  Making sure not to put royal icing over the cake dowels, this will ensure that they are seen and removed.  Then place the next layer on top, use a fondant smoother to press down firmly so it sticks. I also like to wiggle it around a bit to really get it adhered.   Then repeat with the following layers.  You could also add one long dowel down the centre, but it will depend on the type of cake boards you are using weather you will be able to get it through them or not.  Use a pencil sharpener to make a nice point on the end.  Then put the whole thing back in the fridge if you can, over night even if possible so that everything is super cold and firm for transportation.   My favourite thing is no slip matt, like they put in cupboards, put a piece the same size as the box in the bottom of the box as well as one under it on the floor of the vehicle.  

As far as the modelling chocolate, I believe you could either use water as glue or if it is heavier, you could pipe some melted chocolate from a parchment triangle.  They even have spray freeze in a can that you can get to spray on the chocolate so it will harden instantly.  

Good luck and smooth driving! 

The main thing to consider is that the cake will be very heavy, so make sure there is someone else at hand to help you transport to and from the car.

I travel with stacked 4 and 5 tier cakes all the time. I also use Royal Icing to stick the cakes together, although not as much as described before. A generous squiggle in the middle has always done the trick so far and it will not be so difficult for venue staff to separate the tiers.

As to the modelling chocolate branch, I would transport it separately and drape it on the cake on site. You can fix the branch with either some softended MC or with RI.

Have fun!!

Thank you all for your suggestions.  All are very helpful.  I believe the royal icing between layers may be what saves me.  I will also use the no-slip mats as well.  I'm not sure about the branch. I'd like to be able to make it ahead of time and attach it when I get there, but then I'll need to add the leaves and berries to it after I attach it and I feel like I'd be cutting it too close if I run into problems.  Maybe I'll try transporting with everything attached but still have back-up supplies with me in case it doesn't survive.