Trail riding question...

My sister and I have rode horses all of our lives. We mostly just pleasure ride but have done jr. rodeo, cattle penning, and gymkana. We have a friend that trail rides and it sounds like a lot of fun. We are probably going to take our horses out to this recreational area that is designed for horses and leads to a lake. It sounds beautiful. Our friend loves it. Is there any good advice we should know about trail riding before we go? Any special tack or anything we should take along?Thanks!