Sculpting a cake with rice crispy treats?

i wanted to make a sculpted cake and was planning on using rice crispy treats to sculpt in place make wont work in and was wondering can i refrigerate the cake after? or will the moisture make the rice crispy treats soggy. what would i have to do with the cake after im done with it. do i just leave it out side or would i have to cover it with saran wrap or would covering it with saran wrap trap moisture in the cake a ruin it?