I did GTTS Road on a Sunday morning. On bike at 5:45 AM. No traffic at all until about half way up, and then only light traffic till closer to the top. Took 3 hours from Lake McDonald Lodge, which is close to Sprague Campground. I would not discourage anyone from doing it on a Sunday morning. The RVers take forever to get going, others are in church, praying for me, and all the motorcyclists are still hung over from Saturday night, and busy attaching noise makers to their pipes. Just get up early and you have the world to yourself, basically anywhere you go. This was peak season too, on July 28th.
Weather was fabulous. Watched bighorn sheep walk right by me up top on trail to Hidden Lake.
It was Day 1 of a 48 day ride from Canada to Mexico over the Rockies, plus Utah and the GCanyon.
Everyone said it might not ever get better than Day 1. As great as everything was, it never got better than Day 1.
GTTS Road is truly one not to be missed.