MT45 step van RV conversion

[sailor305]

I can get a low miles 2000 MT 45 Step Van from a government surplus which I'd like to convert into RV.
It should go easy with a rectangular aluminium box.
I'm going to replace the rear roll off door by a enclosed box for two spare tires (down) and bicycles above. A sliding door to the drivers cabin is already in place. Probably I may add a side entrance.
For sure the fuel tank has to changed into a 60 gls one and moved to the middle of the ladder frame so i can add underfloor drawers on both sides.

Now the questions

1, There is a lbs 14,140 version with single rear wheels (mine is rated lbs 14,460, dually). I'd like to learn what efforts are required to switch to rear single wheels.

2, The hood doesn't look very modern, there are nicer ones on the market.
Are they all compatible?

3, The van has leaf springs. Can I add airbags for a more comfortable ride?

Is there somebody out there who knows about this van?

Thank you