I first assemble the tracks, and where I can I get rid of the 'pins' which after some handling have a tendancy to fall apart. I use small brass pins cut to size with a touch of c/a (superglue thick) just enough to hold the pin in place.
I then hold the track in place on a length of cardboard and give it a light spray from a rattle can of car primer...
Then apply a coat of silver to the tracks where the wheels touch, and once dry cut strips of masking tape about 2mm wide and cover the whole length of the track where the wheels would run.
As you say you are not into airbrushing - use a soft paint brush and apply a thinned coat of Rust primer to each length, it will dry quickly. Then apply a second and if required a third coat.
Turn the track over and repeat the rust application, and once dry, dry brush the treads where they come into contact with the ground with silver paint.
Turn the tracks over again and remove the masking tape.
I have posted a couple of my tracks to help you....
Cheers
Mike.