There would still be several hundred acres of federal land for all of the governmental activity. The residents of D.C., however, deserve representation and aren't interested in being shoe-horned into Virginia or Maryland.

Yes, Puerto Rico should be a state. Talk about a poor stepchild. With statehood comes a great deal of debt and a need for reform, something PR is badly in need of.

There are other places, like Guam and American Samoa, where laws and rights need to be reviewed. The colonial aspect of holding territories in this day and age should be sorted out. The US and Philippines still have a complex relationship though the Philippines gained independence in 1946. It's the military bases that are a problem for them now.

I just looked up the US Territories, 16 distinct areas:

American Samoa.
Guam.
Northern Mariana Islands.
Puerto Rico.
United States Virgin Islands.
Minor Outlying Islands: Bajo Nuevo Bank. Baker Island. Howland Island. Jarvis Island. Johnston Atoll. Kingman Reef. Midway Islands. Navassa Island. Palmyra Atoll.