2003 and up Express questions please.....

I am looking to purchase an Express cargo Van and have a few questions:

I want All Wheel Drive and Driver's Side Cargo Doors.

1) Can either the driver or passenger side doors be SLIDERS? or do they have to be the 60/40s? (I prefer sliders)

2) I want at LEAST a 3/4 ton unit. What is the exact difference (besides capacity) between the 2500 and 2500 HD. I know the HD has 8 lug rims, is the suspension or other things different?

3) I am looking for 2003-2005 years roughly.

Here is one I am looking at, but I am not too sure about the light-duty 2500 status: VIN# 1GCFH25T931158496
Thanks all!