Lloyd,
I bought a two-gallon kit and had about a half gallon left over. (As I understand it, it has a long shelf life.)
My teardrop is 4' tall x 5' wide x 10' long. I put one coat on the bottom of the trailer floor - on top of two coats of CPES - and two coats on the exterior ply walls and roof.
First thing I did was lightly sand the ply, filled the screw holes with Plastic Wood, then sanded the fill, followed by the epoxy. This picture is after the first coat of epoxy:
Take care,
Tom