I am going to California to look at somw remote desert property surrounded by BLM land. I need to be sure that the specific sites I'm looking at for campsite/future cabin are on the specific parcels offered for sale, and not adjoining parcels or BLM land. Which GPS unit can give my latitude/longitude when I am at those spots and maybe-\-just maybe-\-show me land boundaries? I know the lat/lon of the parcel boundaries but need to be certain that my planned cites are inside them before I hand money over. Seller is elderly and remote and less than helpful in this regard.