First travel to the Claypool waypoint which resides in the Township of Claypool located towards the central west of the region. From here, you will want to travel south along the dirt road, looking at the map, and taking the western road that splits off at one of the forks and travels through a wall that protects the town.
Once on the other side of the wall, look to the left of the path near the water for a small fishing shack attached to a tiny pier. Your vista will be sitting atop the shack.
In order to reach the vista, you will need to look for the crates which are stacked up against the west facing wall of the shack, the side you first see when running towards the building with the directions given thus far. Use the crates as stepping stools and then move to the wooden beams which stick out of the building, just above the crates. Once on the highest one, you will have to face the roof, but jump forward and to the left a bit, as you cannot quite reach the roof if just jumping straight forward. You have to catch the roof just where it arcs down a bit to the edge.
This final jump can be a bit perplexing at first, but at least there is no steep penalty for falling off here. Also you have a fair bit of space to stand on, with your feet hovering in the air, even though the wood beam makes it look like there is very little space to stand on.