Ok, I know there are 3rd party tools and the two hop process to go from Exchange 2003 to 2013 or 2016, but I have only about 10 mailboxes a couple of public folders to move.
With that said, is it possible to simply:
1. Export all the mailboxes to .pst files using the client's Outlook 2010
2. Export the public folders to .pst files also using Outlook 2010
3. Remove the old Exchange 2003 server box.
4. Install the new Exchange 2016 server box.
5. Setup a new mailbox for each domain user and import each user's backed up .pst into their new empty mailbox.
6. Import the backed up public folders (saved in .pst) to a new shared mailbox in 2016.
7. Reset appropriate permissions for the shared mailbox (old public folders)
If it's possible, this seems easier and cheaper to me since I have only a few mailboxes to deal with. I just don't want to tear down the Exchange 2003 box and discover that I can't import the .pst files. I know it's a little labor intensive, but the 2003 box is borderline corrupt and I really don't trust a script to read and move everything and hope it all works out. With my lack of experience with Exchange in general, this seems easier than cross-forest migration, 3rd party expense, or buying Ex 2010 just to use as a stepping stone.