We did this trail last summer for our vacation. If you're just doing a one-day ride, I recommend starting at the Wallace end of the trail and riding back to Coeur d'Alene. We started at the Coeur d'Alene side and rode to Wallace, stayed overnight and rode back the next day.
If you have an extra day, it's well worth the time and money to check out the Hiawatha mountain bike trail.
Here's a link to the webside I made of our trip. There's also a link to our Hiawatha experience at the bottom, so be sure to check it out.
http://www.footeco.com/ellen/Coeurdalene.html