Great video. You have a beautiful piece of land and your family will love it for many, many years. We have built a good bridge in a similar place using concrete bin blocks on the banks of each side. We were able to use steel beams across the bridge, but you could use wood too. Once leveled and installed, the bin blocks do not move. The ones we used were 2' x 2" x 6' and weigh about 4000 pounds. Enjoy your place.