Well spec wise, I have a rack so I may as well use it!!

Wasn't planning to go down the roof tent route, that's a bit OTT for my liking. Was thinking more ground tent, I have one anyway, and will take out the back seats, so will build some form of storage inside with a flat top to allow 'indoor' sleeping in inclement weather/depending on location occasionally.
Never fancied the idea of a RTT lets say in a lorry park or lay-by in Western Europe.

Will be fitting a Waeco CF35 fridge because I have one!! So will be fitting aux battery system, and a small pure sine wave inverter so I can charge laptop etc.

I'm tempted to fit a water tank in the dead space behind the front seats and am seriously considering some form of heat exchanger, but I could just as easily go down the solar shower route. Haven't just made my mind up on that one.

The reason I was thinking of the Aux tank was to avoid having to carry diesel in the cab, especially if its partially used for sleeping, and I don't want the weight on the roof really either??
Have you any idea if any other tanks will fit below, I have a fair collection of scrap here, and I'm planning to do some measuring of fuel tanks versus space. (I buy the odd car here and there to be broken for export). If there is a specific tank out of another model that would work easily I would be able to get it from friends in the trade. Long ranger tanks etc seem very expensive.

Beyond all that, I was thinking tools/spares/jack at least 50kg, something to cook on and some clothes etc is going to throw another 50kg into the mix as well.

Build weight on some form of drawers and sleeping platform has to be another 60+kg at a guess.

I would think when you add all that together (+fuel,+water) that it has to be near 400kg?

As for the winch bumper, well I'd love an ARB on, but unless I can find a 2nd hand one cheap (which I can't see happening) I'm going to make one myself. It won't be as nice but it'll do the job and it'll be a fun project.

Really the way I'm looking at it is that I'd rather spend the money on the mechanicals than the RTT, ARB stuff etc.