You didn't mention your state nor the ghost town so cautions like be prepared for snakes, black widow spiders, etc. may not apply. Another caution is wells and privies that may be hard to spot-until it's too late. Get your tetanus shot (rusty nails, etc.).
I'd guess what is still visible has had the most MD searches--in the last +/- 30 years. I would not start there. I would do research to determine where the town dump used to be (probably not visible now) and I'd start there. I'd also seek out where old ball fields and parks were; any place where people congregated.
Old plat maps of the town would give you this information.
Don.....