The demands for vehicular Internet access are proliferating. Access Points (APs) can be deployed along the roadside to provide wireless coverage and network access for mobile vehicles. However, high mobility may cause frequent link breakages, which will seriously impact Quality of Service (QoS). In this paper, we study reliable routing for Roadside to Vehicle (R2V) communications in rural areas where rough terrain poses additional challenges. We propose a novel routing protocol where the stationary APs play a key role in route maintenance. The protocol includes a prediction algorithm which can predict the lifetimes of wireless links with consideration for terrain effects, as well as routing algorithms which can find stable paths for packet forwarding based on the prediction. Simulation results based on OPNET Modeler and the rural roadways in the Yellowstone National Park show that the proposed protocol substantially outperforms existing ad-hoc routing protocols.