I don't know how common mystical prayer experiences are among hermits. Still, given the fact that hermits are contemplatives and contemplatives pray regularly, intensely, and even in a relatively pervasive way where every activity is marked by openness, attentiveness, and responsiveness to God, I would expect to see mystical prayer experiences with some regularity. This regularity is not the same as frequency, though. Because I accept that mysticism is a function of openness and attentiveness to Divine Mystery (the source of the term mystical), I also believe that those who pray regularly and seriously will have mystical experiences. As I understand matters, authentic mystical experiences are a part or subset of contemplative experiences. This means they come only with consistent and persistent practice.
I don't speak much about mystical prayer experiences because these are, 1) a very personal and intimate part of my life, 2) a gift of God who chooses to come to me in this way in specific circumstances, and 3) these are only helpful to share in limited situations. I also 4) never want to give the impression that God has created me differently from others or that God loves me more or even particularly differently than God loves others. For this reason, I cannot accept that some people are born mystics or that they have mystical experiences because God loves them in a vastly different way than he loves everyone else. Thus, I believe that God wills to give himself to every person in this way and that one needs to develop one's openness, attentiveness, and responsiveness to God in the persevering practices of prayer and penance. This also means that I believe God's really remarkable gifts must be matched by authentic humility and discretion.Your questions about my not speaking about mystical experiences point directly to this demand for humility and discretion. I believe without these two qualities in particular, speaking about such experiences can morph into bragging, arrogance, and the subtle or not-so-subtle denigration of "ordinary" spirituality and "ordinary" prayer experiences or those who have not had and may not believe they are meant to have such experiences. In some people, these kinds of experiences are reported with what is almost a sense of entitlement!
One of the greatest gifts God gave me years ago, and one which, paradoxically, does not conflict with personal limitations or giftedness in this area or that one, is the sense that I am the same as everyone else. This awareness along with my sense that this is a real grace of God colors my theology and mystical theology as well. It helps me to appreciate what God wills for every person; it also sensitizes me to those whose "prayer" experiences are always larger than life and peopled with characters and events drawn from dated hagiographies that are less than edifying in some respects today. Rather than being reminded of a reverent reminiscence of an intimacy most properly discussed with one's spiritual director, very good friend, or one's confessor, this approach to announcing one's mystical experiences far and wide reminds me more of a carnival barker calling attention to circus acts. They strike me as "inauthentic", to put it mildly. I really would encourage you not to share these experiences with anyone and everyone, tempting though that might sometimes be; when the right person, place, and time comes to share, you will recognize it. Just remember, humility and discretion!! This is the way we truly praise God.