I’m an instrument man on a small low budget crew. In Massachusetts terrain string & compass lot corner recon can be tough in swampy areas or thick brier patches. With the help of my Masters ME son I’ve worked out computation of GPS coordinates for plot plan lot corners when I know GPS coordinates for one corner. Now I need to lay hands on something affordable to give me GPS coordinates in the field accurate to within 5 feet or better. With that I could measure the first corner, compute the rest and then compute compass bearing and distance from any location to a target corner as I work around obstacles. Problem is I know nothing about GPS equipment. Accurate and affordable used GPS, any chance such a thing exists? If so, how do I find it? Ideally it would give bearing and distance to a target.