My builder is about to break ground on our new home on a large rural piece of property that we own. There is a connected power pole with a 100 amp breaker box that is hooked up mainly to give the construction workers power for their tools. I also keep my large 5th wheel camper there for occasional stays. The camper has 120v, 50 amp service. During construction, I will be spending a lot of time there and want to provide power for it. The only place I can park it is 150-160 ft from the pole. Here is my plan. Please tell me if it is inadequate or incorrect in any way as I want to do it safely.

Purchase a 500 ft roll of 2 gauge THHN wire as well as a ground wire. I plan to bury the wire in PVC conduit and run it all the way 18" underground to a 50 amp RV receptacle near the camper. Is two gauge big enough to compensate for the voltage drop from the long run? What about the ground wire size. I've been told that 10 gauge would be OK but others told me to use 6. Still others told me to match it to the hot wire size. I can't imagine that I would need to go that big for a ground wire but I'm not an electrician. I even considered just running the conduit on the surface as a temporary installation but I'm not sure if that's legal even if only temporary? Any help, ideas or advice would be appreciated.