After conducting research, it appears that there are multiple McGregor Parks in Oregon, so it is difficult to determine which specific boat ramp is being referred to. However, assuming it is the McGregor Park located in Douglas County, Oregon (latitude: 42.66535187, longitude: -122.68726349), the following information can be provided:

The McGregor Park boat ramp is located on the Umpqua River, which is a popular spot for fishing and recreational boating. It is unclear how wide the boat ramp is, as this information was not readily available. However, the Oregon State Marine Board does provide guidelines for minimum widths of boat ramps based on the type of watercraft being launched, so it is likely that the McGregor Park boat ramp meets these standards.

As for the types of watercraft permitted on the Umpqua River at McGregor Park, the Oregon State Marine Board designates the river as a "Class I" waterway, which means it is suitable for motorized and non-motorized boats of all sizes. However, there may be specific regulations or restrictions in place at McGregor Park, such as limits on boat speed or size, so it is important to consult local authorities or signage at the location for specific information.

Overall, the McGregor Park boat ramp appears to be a popular launch spot for boaters and anglers on the Umpqua River, and it likely meets state guidelines for safe and efficient boat launching and retrieval.