Onx Offroad

Hey y'all, I'm about to go on my first solo off-roading excursion in Hollister Hills SVRA. I've tried to find a good map online or a good trail app that shows the trails for free but can't find any good ones. The only app that seems to offer these features is Onx Offroad for a monthly subscription. Do you guys use this app? Is it worth it? is there a better cheaper alternative? Thank you