I strap my oars to the frame on each side by the oar tower and cinch the oar tether so it's not flapping around in the wind, & leave the spare oar attached on the boat just like it'll be when I launch. I put the counter balances on the front end for tongue weight. Been doing this since I got my trailer in March '03. I've probably got tens of thousands of miles traveling like this, and have never had any trouble or unusual wear on the oars where they rest on the frame.
Nothing in the world is more yielding and gentle than water. Yet it has no equal for conquering the resistant and tough. The flexible can overcome the unbending; the soft can overcome the hard. - Lao Tse