Welcome aboard and best of luck with your new unit. I haven't seen a Monticello yet, that must be a newer model in the Rushmore line. Hope it gives you many good years of happy camping.
Although I could not find the Monticello on the Crossroads website, the model number is RF35MC. The other four units are RF39xx which I assume means they are a little longer. From the dealer's websites that have the model in their lineup, it looks pretty nice. Gone camping has a really nice floorplan.