Well my thoughts are this... the kitchen should stay out side but you should have the shelf inside with a small corner sink a coffee maker and a microwave to have morning coffee and snacks you can heat up. If you could find a refrigerator with 2 doors you could cut a hole in the back and have a pass through fridge for cold drinks and sandwiches inside...
Speaking of a bathroom inside, you can now get a corner toilet, corner shower and toilets that fit in a corner so you can make a bathroom out of a small space. But where are you going to put the, fresh water tank, sewage hold tank and propane tank? I am assuming that since you want all this inside you would be doing more of these activities and want more gas and water/waste water, unless you are only going to rely on shore power, which defeats the purpose of self contained.
I saw a utube video of a kitchen that fit in a big box/cabinet. That box/cabinet was mounted to a frame that fit into a trailer receiver on the back end of his truck. You could weld a receiver to the back of your frame and have an optional kitchen out side, freeing up a lot of room inside...