Hi Susan
The Time required for a metal detecting outing is mostly in research of your area, the actual hunting is a one or two hour process as time allows,
You guys there in NY, NJ and the other States on the east coast have the best hunting grounds in the US, simply because of the populations that were present in early america
I have seen many very nice coins come from those states, as well as many very cool artifacts.
One of the best methods for finding prime areas to look is by overlay maps, I have done this for NM using the earliest map I can find and a succession of later date maps, use matching grid size and transparent copies, laying each over in sucession until you reach present day, look for areas that have remained relatively undisturbed ,by progress !! and then local history to pin point. things such as farms, water ways, homesteads,military encampments,fairgrounds ,and old dumpsites.
Happy Hunting !!
Rick