It is possible that http://www.whitehouse.gov/news/ "News by
Date" links at the lower left of that page might help.
Obviously, some momentous stuff happens (in ANY government)
that is not discovered until maybe much later. But since you
appear to be filling in each date at a time, it can't hurt to
use this as ONE possible means of recalling when certain
things happened. That would require reading through huge
amounts of text, however. Possibly a better start would be
the executive orders. There is a link on the
www.whitehouse.gov page, but The National Archives at:
http://www.archives.gov/federal-register/executive-
orders/2001-wbush.html gives more of a history and summary,
citations to the Federal Register, and links to related
executive orders.

But for this day-by-day calendar, I suspect it will be best
to go to a library (or use remote access to Newspaper
databases at a public or academic library you are affiliated
with). Proquest Newspapers, for example, lets you browse
publications. You could choose New York Times, for example,
and set the "view issues" dates to "April 2002 to April
2002", and scan the 195 headlines for April 16, 2002. Or
probably better - you can set to exact date 04/16/2002 and
search: bush in "citation and abstract" (full text would be
less likely to limit to important events). This will get
unexpected dates as well - one of the 10 hits on that search
is an article about senior administration officials meeting
with Venezuelan rebels "several times in recent months..."
(before they ousted him for 2 days in a coup attempt).

I doubt that there is an easy way to do your project, partly
because very important things often get done unofficially at
first, and also because their importance may not be noticed
for a while. But this is certainly an interesting project,
and we may be able to come up with better ways to do it. I am
leaving your question open - in hopes some other librarians
will chip in with other ideas.