I can't help you on Ford vs Chevy. I think they both will have there problems.
If you go with a box type truck get one where the box sits lower on the back wheels. It will have the wheel wells going into the box. This keeps the body lower for less steping to get in and lower overhead clearance. Also get one where the box is wider than the cab.
I have been looking as somthing like this: http://www.supremeind.com/html/parcel/cargovan/ford_cargovan.html
This one has storage doors on the outside: http://www.supremeind.com/html/service_bodies/spartan/chevycutaway/main.html
They come in Ford or Chevy 10,12, or 14'. Other body builders make something simular.
I see them advertised between $20-30k. Sometimes cheaper than a normal 1 ton cargo van.
If going this route I would get the 12 or 14' version. I have a 12' step van body and it's not much problem. Step vans are great also but hard to come by. Also they don't have much except metal in the cab so they are cold and noisy.
Watch the GVWR. For a box 9K max is probibly too low. 12K is a bit strong and may give a hard ride. If the GVWR is too high it may limit the roads you can take.
Ford clips why they think they are better: http://www.fordvehicles.com/trucks/f150/truth/index.asp?id=frame
No EPA econimy on biger trucks. I have looked up EPA ratings and HP on 1/2 ton P/U just for comparison:
Ford 4.6L 231 HP 16 city, 20 mpg hwy
Ford 5.4L 300 HP 15 city, 19 mpg hwy
Chevy 5.3L 295 HP 16 city, 20 mpg hwy
Chevy 6.0L 345 HP 14 city, 19 mpg hwy