We went to the RV Supershow in Tampa yesterday and all the 5th wheels we looked at had the island in the kitchen. We think that takes up too much floor space.
As full timers we're not trying to make 500-600 miles a day. DW brings her Thermos of coffee an I have a bottle of water maybe one potty stop during our 5 hrs on the road. No need to access anything other than the potty room. I'll take an island for more prep space.