This season alone, I have had several requests to take private photo tours into the “The Sea of Trees.” Twenty plus years I've been camping/hiking exploring the Mt. Fuji area.
As with any forest, it’s easy to get yourself turned around, then poof lost. The Sea of Trees, at times naturally produces strong magnetic fields, being at the base of Mt. Fuji, disruption compasses. Thankfully we have electronic compasses, with industrial GPS’s along with satellite phones. The consumer grade ones work just as well. These devices have guided myself/team/clients-friends back to our vehicles more times than I can count.
While in the forest we always carry more than one GPS, just in case, along with a spare satellite phone.
If you are going to visit the "The Sea of Trees" and hike in the forest, it's a good idea to stay on the recommended trails with or without a guide. There are dozens of trails that are well groomed & safe. Annually thousands of elementary school children of Japan, visit the forest on School day trips. The forest is always a joy to visit, with landscapes trees never ending, along with thousands of caves, bathing spots, the adventures never end.

Happy Zen Photography