>>38213222 yo NEET here and I sort of know your feels. My stay in the woods is limited by my shitty cellphone battery, as I must send a text three times a day detailing my position. Still my mother guilt me by saying how she's unable to sleep as long as I'm gone.
Just stash all your gear in some hidden place the day before you head out and tell her you're just going to some convention or whatever for a couple of days. That, or simply force her to accept you're an adult.