Definitely blank out one window on each side, probably 2 would look even better maybe.
You only need a single power truck. You would be able to pull one or two trailers with that. The AAR trucks are the same look as an Alco 4 axle diesel.
You have not mentioned if you want to power 2 or 3 rail. If 3 rail, any truck out of a diesel from MTH or Lionel, or even Weaver. They have all done Alcos and would be something that would pass. The back truck should look the same but can be a dummy. It would be neat if you make it shorter than the front one as on many prototypes. Perhaps use a passenger truck.
For 2 rail, MTH and weaver die the trucks with motor on truck also. Another option is a drive from P&D which is a descendent of the weaver single motor drive. Just power one truck.
Make a frame/floor out of some very good 1/8 inch plywood or 1/8 styrene.