Camping bus base – Ford Transit or VW bus?

Hello! We would like to buy a camping bus in a few months. By 2013 we drove for over 9 years a VW-T4 with a canopy (unfortunately sold because I needed money at short notice) and it itches again, the camping virus and is looking for a vehicle for many years to use. I am looking for something in the price range 35-40k€. Regardless of the interior layout – what is to hold the then from the base vehicles? Current transit or later VW-T5, early T6? A little appalled I am from the engine’s origin ot. The vehicle is supposed to replace a car in everyday life (about 4tkm short distance p.a. + holiday trips also about 4tkm p.a.). I would like a petroler. Petroler is not available at the Ford and the VW-T6 currently 150hp(or more) – which gasolineers were there at the late T5? But it will probably be a pin search to find a VW camper with petroler. (in the T4 I had the VR6, was good thirsty, but with my low Jahers driving performance I took that in buy) I find a diesel at short distance (m Ax. 8km, but mostly I less), which makes up the half-yearly driving performance, somewhat unsuitable? What does it look like with the rest of the technology? Preparing for rust at the Ford? Buying a VW diesel? Thank you!