I owned a Libero, which had the same floor plan as the Serenity. I chose it because I preferred the Chevy (no diesel) and didn't want to deal with a slide that I didn't need.
Give the factory a call. They are super people to deal with. Personally with the top quality of the LTV builds and organization, just choose the floor plan that works best for you.
If I were considering full or half time, I would go with the Wonder because it has the floor plans that I like best... on a Transit, which is likely easier to find service than the Sprinter... and no slide.