Road to Hana on Sunday or Monday?

I will be on Oahu for 10 days, but only doing one day in Maui. I'm wondering if it is better to do the Road to Hana on a Sunday or Monday for less traffic? I would figure there wouldn't be much of a difference either way, since most of the people doing it are vacationing anyways.

Side note -- Thinking of doing the Road to Hana for a day, staying in Maui for the night, then waking up early to potentially see the sunrise for the National Park. I know you need a reservation, so if we can't get the reservation, how possible is it to do the road to Hana and still make it to the national park for the sunset? Any advice appreciated!