tmillpond....
The streams in the Black Hills are super fun, and absolutely perfect for a 10 year old to learn. It should be a trip of memories for a long time.
Rapid City is about 5 hours to the Northeast of me and I use to get there quite a bit for work and since it was usually a drive rather than a flying for me I always took a rod.
The steams in the Black Hills are very different that streams that most of us are use to. They are spring creeks that originate in the hills but never make it out of the hills. The landscape made up of porous sandstone so the streams seep back into the ground before they exit into the plains..
There is a Fly Shop in downtown Rapid City "Dakota Anglers & Outfitters" on 7th street that is open 7 days a week (not normal for fly shops). The owner Huns and the store manager Dave are super nice and extremely knowledgeable. If it is in your price range for you I would highly recommend that you hire them for a guide day. Your son will learn a great deal from them. If that is not affordable, no worries, just stop in and ask for information, they will give it freely and give you up to date information on what is fishing the best at the time and what flies to use. They can also hook you up on flies and I know they will mark-up a map to show you right where to start. Their web site has a ton of information on the Black Hills; current reports, hatch charts for flies, etc:
http://www.flyfishsd.com/guidedtours.htm
In preparation for your trip I would recommend that you get your hands on Steve Kinsella's book "Trout Fishing in the Black Hills". It has great information on both the streams and lakes and complete with maps and techniques. It is only about 150 pages and and easy read that you and your son can go through to get excited about your trip. You can purchase the book on amazon, or you can buy it from Dakota Anglers on-line:
http://flyfishsd.myshopify.com/products/trout-fishing-in-the-black-hills
The streams in the Black Hills because of there nature can change rapidly so the information gleaned from the fly shop at the time of your trip will be the best.
I will look through my Black Hills log book and post some areas I have noted as really good. It would help to narrow down what month you are going since that may change what is best.
I an sure you will have a great time.
[This post was last edited on 4/14/12 at 9:38 AM]