You have to go back to Chengdu Ring Expressway first, then go south to Pengxi Expressway, and then to Longdong-Dashi-Jixiang. The toll is around 50 yuan, or take National Highway 3 18 to Lezhi, Suining-Dashi-Jixiang, because Jixiang is not far from Dashi, and Dashi is on National Highway 3 18. The specific toll is not clear.