It's extremely attainable, it just depends on your fitness. For those in reasonably good shape, it would take ~6 hours to go up via MR and ~3-4 hours to come down. I've day hiked it twice and both times started at around 5-6am and finished by 3-4pm.
Some tips:
1. Study the route and download a .gpx file to your phone to ensure you don't go off route.
2. Be comfortable with 3rd class terrain.
3. Be comfortable hiking at altitude for hours and hours.
