Hi! I am also new here. The first thing I notice is how friendly and supportive the more experienced members are.
I know I have not much to contribute but I do enjoy participating. So let me just state the obvious - a van like yours will probably not become a fuel sipper overnight. May be it never will. However, one often forgets that just good and proper maintenance can go a long way to make a vehicle stay as fuel efficient as it can be. The rest is then up to you. Actually, I mean up to the driving style that you choose to adopt. Obviously, because you carry passengers, some rather drastic measures may not be suitable for you
. However, things like better oil (synthetic?), tires (LRR) etc can still help. Also, don't forget to turn off your engine when you want to stop for a long enough while.
Safe and happy motoring!