Here's a great link with trail information:
http://www.fs.usda.gov/wps/portal/fs...rest-%20Hiking
We like the Centennial Trail, in all its various loops. Some parts are better maintained than others — more important for biking than hiking. We probably won't do the Mickelson Trail Trek. I like quiet. DH and I like to go when the trail is less likely to be crowded. If we didn't live here, the Trail Trek would be more tempting. We do parts of it as we have time on the weekends. I've never ridden the whole trail end-to-end in one ride. Enjoy your time in the Hills. Hill City is one of my favorite places. Depending on your feelings about German food, you should go to the Alpine Inn for lunch!

Deb
PS If you still have a saddle left later in the year, I'd be interested. I can't really spend any more right now.