Somebody sold me several Red Caboose kits at a reasonable price years ago, so I have been turning them into various B&M engines. My GP18 is 1750, with the Bicentennial Minuteman on the nose. The dynamic brake is modeled as removed, with a plate welded over the opening. What I have used to power it are the power trucks and reversing unit from a K-Line MP 15, which I attached to a thick piece of brass stock. This doesn't look as bad as you might think, and it makes for a great puller. The MP 15s used to be pretty inexpensive.
I used a Lionel short hood that I had hanging around. Scale coupler and railings on the front only.