There are so many riders on GMR now that you won't be totally alone. I've stopped to take a break and have drivers ask if I'm ok. That's on the weekends and weekdays.
During the week, there are usually forest dudes and construction people around somewhere. Not like you are going to be out there for more than an hour without somebody seeing you. Few motor cycle dudes too. They are cool if you treat me as such!
On a hot day, take atleast a spare (3rd) bottle in the jersey pocket. No special tools required.