I have a similar van, though a size class smaller (Mercedes-Benz Metris; the only one sold in the US in that size class) and we did SOME of the upfitting you se

I have a similar van, though a size class smaller (Mercedes-Benz Metris; the only one sold in the US in that size class) and we did SOME of the upfitting you see on these. L-track the full length of the back that the bench seat is in and can slide along, swiveling front seats, standalone power system, insulated window covers for every window, and planning on the Westfalia style roof tent that is available. It tows 5,000 lbs, has a 2,200 lb payload, and gets over 30mpg at 60mph on the highway (32.5 yesterday). Most practical vehicle I've owned, but as I said, we only did a partial upfitting as we don't need the "living" stuff, just the "camping" and flexible use stuff (my son is autistic and it's his space when he can't handle grocery shopping, etc.).