Trailer frame assembled. Here's a very rough (not to scale) sketch:
Down the road I'm hoping it'll look a bit more like this:
When I asked my father his opinion on what color I should paint it, he said that because black is the fastest color, it's probably also the most aerodynamic. Thinking of just extending the car's color scheme, though I might add a stripe somewhere.
EDIT: Top view, without the addition of fenders