Flying to Denver from Norfolk, VA...want to rent a car and drive back...any suggestions on which rental company to use?
First run of thumb is to always rent from the majors - Hertz, Avis, National, Enterprise. Secondly, you should check everyone as each may factor in the one-way differently. For sure make sure you get something with unlimited miles. And look at the drop fee. Be very careful as some companies do one-ways based on a mileage rate and you would get killed there.
I would also suggest to NOT do this rental at the airport as you'll incur significant additionally daily fees. Get your rental off airport such as I-70 and Quebec or downtown.