I have the RV4. I didn't think I needed the RV5 because I usually only have two campers and use the awning area as living and eating. I bought the floor saver which gives a groundsheet under the main awning but need to get some shadecloth for the open section. I will be getting the fly as there is some condensation inside, but it never leaks.
The kitchen in the car is what I made for my Vitara held down with tiedowns. There are photos on this thread earlier. It is made from Capral Aluminium Cubleock which has different plastic connectors to join 25mm Ally square section. Also used some Plywood, and marine carpet. The fridge slide is a 100kg drawer runner from Hafele kitchen supplies but there are other cheaper options to do this.
Here is a pic of the kitchen/storage rack in use under theOz tent:
You can see the power lead to the flouro in the tent n the right and the tap on a hose on the right to clear the tailgate. Note the black tap at the Jerry can to isolate the hose for no leaks.
Rod