I am wanting to make a Paw Patrol lookout tower for my sons birthday. I was going to make the tower out of rice krispie and cover with marshmallow fondant. My question is how far in advance can I make it. I dont plan on anyone eating the tower. It is just going to be for looks as we will have other cake. His birthday is on Saturday. I normally juat make my cakes and decorations the night before but I dont want to chance it with trying the tower this time. 

you can make it now -- use your microplane to smooth the surface after it sets up and if it's very tall build it around a dowel that you can stick into the board for stability -- and consider using modeling chocolate it's more user friendly -- but mf will work --

If I use modeling chocolate, still cover the treats with either BC or melted chocolate? Also, i have read some people don't have a problem with the chocolate holding up in warmer weather and some err on the side of safety. The house will be around 75 degress, that wouldn't pose a problem would it? I have never worked with modeling chocolate but have been doing a few searches since your reply and it does seem to be a more user friendly option. 

chocolate melts in the 90 degree realm -- modeling choco might be soft in the mid to high 80s but you won't be touching it then either -- 75 is fine -- no i don't use icing over my rkt because i scrub it smooth with the microplane --

practice with the modeling choco in advance if you think you wanna try it -- be sure to get your corn syrup as warm as your chocolate before you combine and be prepared to stir efficiently before it sets up --it's really very easy --

and depending on how tall this it -- you also might want to consider using crushed rice krispies that you whirl in the food processor first -- i use 5 c rk, 1/4 cup real butter, 16 0z marshmallows, and some vanilla to make mine whether i use 'full strength' rice krispies or if they are powdered down in the food processor -- if they are not crushed i microplane them smooth -- if i use crushed then no need to use the microplane and they are stronger that way