Southern Ca to Coeur d’Alene Idaho

Hello - we are planning a 3 week road trip late June from so cal to Coeur d’Alene Idaho. We want to stop at the Tetons National Park and Yellowstone. Looking for best route and campgrounds. We are towing a bumper pull 30’ toy hauler. We don’t want to come back the same way so looking for different routes and places to see.