Eckert's books are historical FICTION, so I wouldn't rely on Eckert's books for any sort of documentation.
While that series does give a fairly good overview of the culture of the period, there are waaaayyyy too many inaccuracies to take anything in those books as gospel.
While Eckert did do a lot of research to prepare for writing that series, many of the place names and locations are wrong.
Most of the characters are fictional, and much of what is written is based on folklore and tradition, as opposed to documentable history.
By all means, read Eckerts "Wilderness Series" about the American frontier, but take them for what they are. Entertainment and good fiction, nothing more.
As to trapping, the longhunters were interested in harvesting the most valuable animal hide they could find. At that time, deer skins were the most valuable and easiest to harvest and preserve.
The second most valuable commodity harvested by the long hunters was probably buffalo meat, salted and packed in wooden casks. The hides and meat, depending on the hunting party and thier means of transportation were shipped back to the settlements and sold for profit.
Larger hunting parties organized by trade companies transported their hunters by boat to prime hunting grounds. The hides and meat, in turn, were transported back to the base of operations by boat.
Small private parties of individuals, using primarily horses for transportation, primarily took hides, as wooden casks of meat would have been nearly impossible to transport across the moutnains.
Though trapping might have taken place by the long hunters, I have never read of anyone, other than NDNs using steel traps. Steel traps were a trade item, but I have never seen any reference to anyone using them, other than seeing them on trade lists.
I would suggest that anyone interested in learning about longhunters and 18th century trade find the book, "Deerskins and Duffles". I don't remember the author, but it contains a wealth of information.
J.D.