Having tried a number of bitless bridles on a couple of my horses, I highly recommend the flower hackamore. It does give a bit of poll leverage, but not like some bridles, and does not have the cross-under action of the Dr. Cook style bridles. Halter/rope halter type bitless bridles don't have enough control since they move around on the face. The flower hackamore has a lot more precision, stays in place very nicely (allowing you to give specific cues) and with my spooky mare Kodak, it gave me the same control as a bit. Rusty also goes better in a flower hackamore than other types I've tried on him.
That being said, spooking and bolting, as well as getting a horse under control, have more to do with training than tack. Was your horse reliable on trails before? If so, I'd try it with the bitless bridle, but start slow, with short outings. If your horse is the spooky type, then that should probably be addressed with training before heading out on the trail - regardless of whether you use a bit or bitless. I speak from experience.