I ride alone all the time, but will avoid bigger features or features/trails i'm not 100% confident on if i'm not with someone else. However, big stacks can still happen on a section of trail you've ridden a thousand times, so you never know. I have the emergency app ready to go that will provide location coordinates to emergency services. Just need to be in a well enough state to be able to use my phone!
Plus I make sure my Strava beacon is always running, so if i haven't moved in a while and i'm overdue, then someone will know where to find me