The marriage bond would be at the courthouse in Leesburg, as would the entry for the land deed. Check the courthouse website for information on how to get copies directly from them.
The personal property tax lists would be available only at the Library of Virginia on microfilm, as those are of copies sent to the Richmond auditor each year. The courthouse in Leesburg no longer has their copies. The Library of Virginia would also have the land deeds on microfilm.
I know someone who has researched McKim lines in Loudoun. If you email me directly I can give you her email address.