I have the same year, layout and engine B584 as nickkdx, but mine's the Classic version (and LHD). It's a great layout as it gives a great amount of volume inside in a compact van. I prefer the version I have over the one (like yours) with the full height fridge cupboard, as it's a bit more open around the kitchen with that bit extra bench space too, but I'm guessing you have an oven.
Mine has the 2.8jtd engine and I got a Racechips doo dah which supposedly gives extra power and/or economy. I'm not completely sold on the benefit of it, but I did get great economy for the type of driving I did in 2019 - Quite a bit of Alps driving in amongst the 8800km I did. I tend to drive at max 90kmph or less as a lot of my driving was on non motorway roads in France on the 80kmph roads and I got 9.9 litres per 100km (28.5mpg). I wouldn't think the 2.5 would be much different.
You most likely have the Electroblock 99 (EBL99) which has limited battery (100Ah) and solar capabilities (if you connect it through the EBL). The most solar you can connect via EBL is 200 watts as it only has 10A capacity. You can also connect straight from solar controller to battery if you want more solar. The only drawback is the solar charge then doesn't display on the van controller screen (no big deal as you just get an LCD screen for the solar controller).
Read this site which has great info about this EBL:
One of the few drawbacks to the B584 layout is limited external locker space. There is the full width flat one at the rear, but not easy to utilise it. I have a ladder in mine.
I find the drop down bed great and for extra comfort I put in Froli plastic springs which give about 50% extra sprung depth. Not quite so good for the person stuck next to the windscreen, but there's always the sofa bed if they want extra space.
The fold down table mod would be a good idea (though I've heard crazy prices for doing it). Be careful about dropping things on the table and benches as it's very easy to go through the surface of it and I'm still trying to think how to repair it. It's just a thin laminate over a honeycomb of cardboard (like a hollow core door).