I think the problem you will have is having a rear living area AND an island. The island is going to be in the middle and, with the slides in, I don't see how you could get access to the rear unless the island is tiny. In which case why have it. I've seen rear living designs without an island, and it looked like you could still use the entire living space with the island in.
We have a TT with the design you're considering (rear living with a kitchen island). Awesome floor plan and, while we can always access the bathroom, we have to open the slides to get to the rear area or open the frig.
