SR 243 begin at SR 74 in the San Jacinto Wilderness near Mountain Center , Riverside County as Idyllwild Road . The highway traverse north along a winding road through the community of Idyllwild . SR 243 make a left turn at the intersection with Circle Drive and continue through Pine Cove . The road continue through the forest past Mount San Jacinto State Park through Twin Pines and the Morongo Indian Reservation before making a few switchbacks and descending en route to the city of Banning as the Banning Idyllwild Panoramic Highway . The highway continue as San Gorgonio Avenue into the city before making a left onto Lincoln Street and a right onto 8th Street and terminating at a diamond interchange with I @-@ 10 .