Topwater needs would be satisfied with several surface plugs, such as Striper-Swipers, Creek Chubs or Zara Spooks, in a variety of sizes, erring on the large side, in chrome or shad colors, and a handful of large minnow lures in different colors. The man with all these lures probably has an unnerving glint in his eye. Most fishermen do fine only using one or two of these groups, and perfectly competent fishermen show up with only the lure on their rod and a spare. One really nice aspect of river fishing is that you can visualize where the fish will be by looking at the water. The surface of a river will tell you all about what is underneath it.
Stripers are highly structure oriented.
Structures you should look for are current breaks and seams. A current break is any aspect of the river that changes the flow of the current. Current breaks include the traditional rocks, downed timber, and bridge pilings, but they also include chutes, where the current is narrowed and sped up, and holes, where the current eases and an eddy is formed. Current breaks create seams, the primary structure a striper relates to. Another portion will be fish that followed your lure from the seam to the strike point.