Bare with here guys........

I've got a aerial photo of about 5,000 acres that is zoomed in enough to where it would fill up a 8x11 page...... Here is my delima.... I'm looking for a coordinates grid that would be in perhaps 1 inch squares..... When I scout this area by boat I would like to take the map along and by using a GPS be able track where exactly I am on the map within a reasonable distance....... Is anyone aware of a software or website that puts a coordinate grid on maps? It's needs to be detailed coordinances, carrying out 4 places past the decimal....

Thanks for any help..