In regards to your door rattle. If you are comfortable with taking off the door panel I would start there. At least it would allow you to look inside the door to see if something was jarred out of place when the wind blew the door out of your hand.
if nothing is obviously visible with the door panel still off, I would drive the truck for a few miles over several different types of road surfaces. This should allow you to isolate where the noise is coming from and what is causing it.
Just make sure that when you remove the door panels you do not lose the small plastic pieces that are used to secure the panel in place as they are expensive in the amount of almost $6.00 a piece, at least in WI anyway. I lost one while fixing a door rattle on my truck.
Additionally, as someone else mentioned above, closely inspect the door hinges. Although, I don't think that under the circumstances you described it would be a door hinge I certainly wouldn't rule that out either.
I almost sounds as if some of the weather striping may have been misaligned. You may want to consider checking the weather stripping around the entire door.
I Hope this tidbit of information helps.