Unfortunately, using your phone for your navigator is your limiting factor. You are totally dependent on cell tower signals. In the forests, this is spotty, at best. A real GPS is better.
Actually, I find that as long as I can get a satellite link, my Droid nav works fine. Lack of a cell tower does not seem to affect the mapping or the nav function. Oftentimes I will find myself in places on my Droid map, but unable to make a phone call. The key is the sat link.
I expect today's smart phones to be the death knell for traditional GPS devices very soon. Ditto for Sirius/XM radio. Pandora radio is free, and infinitely more useable.
Might be time to sell all that Lowrance and Garmin stock, LOL!!