Bill from Springfield, IL on 8/5/2024 7:51:34 PM:
All 4 tunnels are located north of Hill City
Hill City Milepost #60.
Tunnel A MP #72
Tunnel B MP #73
Tunnel C MP #76
Tunnel D MP #85 (Just north of Rochford.)
This map may help you with elevations.
https://gfp.sd.gov/userdocs/mickelson-trail-map.pdf
Hill City north to Deadwood (IMO) is the most scenic and definitely the most wooded. South of Hill City it's still scenic, but mostly flat, open, and can be very windy on some days. You'll find bridges all along the trail. Enjoy.