When I first became interested in reenacting as a Berdan Sharpshooter there was nobody else in Michigan at the time doing the impression. Interestingly, Curtiss Poole was in the same fix until we ran into each other at the Carleton Park/Hastings event in 1995 and Co. B. was born. Before that, I was in contact with Tom Carton and John Carey of the New York Company, who sent me their uniform guidelines, drill manual and encouragement (remember kids, this was the 'dark ages' just before widespread use of computers/internet--everything went by post).
To prepare my brain for the intricacies of skirmishing, I borrowed the same procedures used by the MAC-SOG special operators to train the the native Vietnamese Yards and Nungs for cross border missions into Camodia/Laos. They would create a sand table model of the area they were to recon and give each Yard/Nung a plastic soldier to represent themselves and rehearse the mission. The natives quickly grasped the ideas and became excellent soldiers in the field.
I used coins or plastic soldiers to make up comrades in battle and then, using Heitman's tactics and later 1862 US Infantry Tactics; would deploy my 'skirmishers', advance them, advance/retreat firing, etc. While it is not as dynamic or fun working with human beings, it gave me a soid foundation from which to work. Once my son, Chris, was old enough I could get his friends to play 'war' and teach them skirmish tactics (yeah, I know-poor kids).
In Michigan, we had a Federal unit whose impression was the 114th Pennsylvania Volunteers "Collis Zouaves" that was designated skirmish company for most MI events. I fell in with them until the USSS was able to field a platoon and were given our own missions. Most of the Federal units of that time did not skirmish and preferred to let the 'odd balls' go out instead. Gradually, the Midwest units learned skirmishing was part and parcel of the majority of CW units, so gradually incorporated the drills into their impression.
You might check out what Minnesota reenacting units are in your neighborhood and see if they do skirmishing. If they do, great. Buy "a set of blues" (blouse/trousers-keep the green cap) and take your Sharps along-learn the drill. It is easy to feel uncomfortable starting out with a unit of strangers. But if your love of the USSS runs deep you will shrug off the discomfort and immerse yourself into the experience. Then learn to recognize the skirmish bugle signals. You will be on your way to becoming an accomplished skirmisher that most units would want to have in their ranks. Also, don't be afraid to fall in with the infantry and learn the School of the Soldier and company/battalion manuvers. Co. 'B' really came into it's own when we outdrilled the seasoned infantry companies. Going from being the 'odd balls' to one of the most respected units on the reenacting field was because of our shared vision, determination and comraderie.
Hope this helps.