Bolt Cake

Hi, I have been asked to make a Bolt Cake,(Disney Dog). This isn't really a problem except the mom just told me her son doesn't like cake that much and she needs it on Feb 20th. I have used RKT before but only for small things. Just wondering if it would be too heavy and if they would dry out if I made it the day before. Also if i decide to make the whole thing from RKT does anyone have price ideas?

Thanks so much.