The main problem I see is climate in your truck. If you don't need all that fancy stuff in that mobile office, just get a tall camper shell and then add whatever furniture items you need. But working inside a camper shell is always going to be too hot or too cold. I assume you'll be near someplace where you have hookups so you can get portable electric heaters pretty easily. Portable electric air conditioners that work are a little bigger and more complex but you can't get those too. If it were me I'd make the kids play outside and then I'd work in the trailer.