Originally Posted by kerry

Ditto.
You've only got 600 miles to go. Even if it's using a quart every 50 miles, it's a manageable distance as long as you stop and check the oil frequently enough. You'll have to stop the engine to check the oil and it will take a few minutes for the oil to drain back down so if you check it within 5 minutes of stopping, I wouldn't fill it completely up to the top mark because there will probably still be some draining down.
How much have you used in total so far on the trip?

By the way, the roads in Denver were horrendous this morning. Three inches of solid ice on all the side streets. I hope you don't run across these same conditions in western Kansas. Be prepared to hole up for a night if it happens. I've tried to drive across western Kansas in those conditions and regretted it.