A temp fence will work. Is there access to water for the horses? Bring hay/grain, med kit for your horse and you, brush, hoof pick, water bucket, obviously a halter and lead rope/s, grain pan if you feed grain, knife(Leatherman's are nice but any will do.) Do you have saddle bags, cantle bag or pommels available? You don't need them all. I now carry a compass on trail, you can't always count on cell phones. Dress according to the weather, maybe a snack on trail would be an option. It sounds a tad much but after you camp time and again, it becomes second nature as to what you need. Don't forget to enjoy the experience.