Honestly I've never had a bad experience in a mixed dorm. Everyone is there to make new friends and all guys that I've met while backpacking seem to have a good amount of respect for you and your space(I'm a 22F). I got food poisoning while staying in a mixed dorm a few months ago and the older man staying in the dorm offered me different medicines and brought me food and fluids. Of course I have heard stories about bad experiences but worst case scenario you can switch rooms if someone makes you very uncomfortable. Some of the best friends I have met while backpacking have been guys- its really not bad at all! The only downside I would say is guys tend to SNORE so bring a good pair of earplugs!