I am baking a cake in September and I'm covering the cake in fondant.

This is my plan:

Bake cake Wed Or Thursday night
Friday afternoonish/evening Put cake together
Saturday Early Morning Drive 4 hrs Destination.

My Question is, After I decorate cake on Friday night with fondant... its it okay to put the cake in the fridge? How would the fondant react if being cold in fridge and than bein in the heat for a 4 hrs drive? Will the fondant go bad?

Is it better to not put it in the fridge and just leave it out at night covered?

Note: the fondant will be hand painted as well.

When I made my Son's wedding cakes I wasn't able to put them in the frig because I had too many tiers (I made 9 different tiers, along with his carved zombie head cake) so I left them out overnight with the A/C turned down to keep them cool.

To insure the cakes didn't slip off the cake board during the drive, I put some RI on the cake board before I placed the cake on top if it (worked great).

I also purchased some of that rubber mat shelf liner and placed each tier on top of a cut piece of that so the cake boards would slide around in the trunk of my car. I lowered the back seat so the A/C would reach back there to keep the cakes cool. (the cakes didn't move an inch)

Now, I not sure what you mean by "put the cake together", but I'm not sure if I would drive 5 hours with a 3 or 4 tiered cake already stacked. I did a lot of "break slamming" due to the crazy drivers on the freeway, and was really happy that I had left them as single tiers for the drive, and then stacked them when I got to the reception site.

Now, my Son's Zombie head did have some sagging around the cheeks, and the tiers has some very small stress fractures, but they were so small nobody even noticed (but, you could use some RI or buttercream in the same color as the fondant to "fill-in" the stress fractures, if you get any)

I hope this helps!
Tammy