You can find it by surfing for sure.
Also if you want to make sure to get roaming Pokemon 100% in a route, try going between Valley Windworks and Route 205 and keep going back and forth between the routes. That will cause the roaming Pokemon to change the route they're in. Keep doing that until one of them is in your route.
P.S: Have a level 45 Pokemon with you to find the roaming Pokemon with Max Repels(Hopefully you get what I'm saying o3o)
Hope I helped!