Router - What setup is best for distance

If its a standard comcast modem setup, then any router would work. Again, thats contigent if its your standard setup. If its just the campsite give you an ethernet connection while they control the router setup, then you might need an access point (most routers have an access point mode). Tough to tell of the limited info. 

but distance will be an issue for several reason. 

1. is because most campers have a metal exterior. this tends to make them giant faraday cages and block wifi. Not condusive to wifi. 

2. Distance is an issue. broadcast power is set by the fcc and routers have maxed it out for a while. so you're not going to get a whole lot of different range out of different routers. the reason point to point systems can reach a lot further is that they're directional. They broadcast all their power at a point. 

3. An option? A basic dual band router in the camper because its not going to be hard to cover full range in the camper. Then use an outdoor access point for exterior to the camper. mount it exterior to the camper (maybe slightly raised like the tv antenna's on campters) and run a wire inside the camper to connect to the router. This would give you coverage inside the camper and some range external to the camper.