Nope. Regardless of what KBB or Edmunds says.

You could get by with a shortbox if:
1) You're not towing often/far/fast/heavy.
2) You drive well in advance of your actual position on the road.
3) You ensure you have working trailer brakes.

Otherwise I agree with what everybody else suggested.

If you want to bump up your budget a bit I know where there's a tricked out '78 shortbox 2wd with zero emissions equipt. from the factory available.