I don't disagree with anything anyone has said thus far -not even Whitjr! I'm the guy who will tell you that seed from other areas will work fine. However, he is correct as there are differences in the plant characteristics sometimes.
You don't have to get Dr. Person's original book. The latest version he and Dr. Davis did has much of the same information in Person's section and some new stuff from Davis.
http://www.amazon.com/Growing-Marketing-Goldenseal-Woodland-Medicinals/dp/0865717664/ref=sr_1_9?ie=UTF8&qid=1424825726&sr=8-9&keywords=scott+persons
There are other books out there which are targeted mostly for beginners. You would have to look around the web to find some of them. Most will have some useful info for you.
Now, to the crux of your questions. Lenno hit it on the head. No way to answer those questions with any authority at all. The best anyone can do is speculate.
I recommend a different approach to my customers and friends, however. Crop in crop out doesn't really work well for ginseng. Particularly when you consider replant failure in the equation. As a new grower, plan on a several year learning curve and then never stop learning. Plan on a number of small test plots this fall to see what areas the ginseng does the best in. What conditions does it seem to like most. Then, you can start planting in earnest the following fall after preparing the area through the next summer.
I think the key to wild simulated ginseng is to never try and cut corners or shave time. More and more I'm recommending no soil additives. Let the ginseng grow naturally and if the ground is suitable, you will have a superior product in the end. I currently am recommending the establishment of naturally reproducing patches through the wild simulated method. Let me explain. If you plant seed wild simulated and let it go, by about the fifth or sixth year you will start seeing babies you didn't plant. If you only selectively harvest the largest roots carefully leaving the area as undisturbed otherwise as possible, you will maximize your profit by only producing the highest quality roots which the market wants and is willing to pay for, and you will not cut short the maturation of the remaining plants which will continue to grow and reseed naturally.
The more seed you plant the more mature plants you will have eventually, and the sooner you plant them the sooner some of them will be ready. I'm speculating that at ten years, only about 40% of your plants (which are 10 years old) will be large or larger in size and ready to harvest. By leaving the smaller roots, they increase their age and size, and when they become large enough to harvest they will be more valuable because of the increased age. Additionally, that plant will continue to produce seed while it keeps growing.
Seed. The others are correct. It is nearly impossible to harvest a commercial quantity of seed from wild simulated plantings. not impossible, but nearly so. Plan on picking every ripe berry every other day if you want them!
Don't get discouraged, but look from a different perspective from traditional gardening/farming and realize that you must produce ginseng which the market will want on a continual basis or about the time you get it down you will be out of ground.