After conducting research, it appears that there is no specific boat ramp named "Box Bar Shoreline Area and River Access Point" in Arizona. However, there are several boat ramps in Arizona that may fit this description or be similar.

One such option is the Box Bar Recreation Area, which is located along the Salt River in Tonto National Forest. This recreation area provides access to the river and has a boat ramp for launching watercraft. The ramp is described as being wide enough to accommodate multiple vehicles and trailers at once. It is unclear from available information what types of watercraft are permitted on the Salt River at this location, but it is likely that motorized boats, kayaks, canoes, and other similar craft are allowed.

It is important to note that information about boat ramps, including their names, locations, and features, can change over time. It is always best to consult current and official sources, such as state or federal park websites or other government resources, for the most accurate and up-to-date information.