I would do a couple things. First would be to leverage Windows offline folder and synchronization features.
I would use a network location, that everyone can access. Then have them create off-line access to it.
This will accomplish your sync and allow your path to remain the same for everyone.
Windows offline folders work this way.
So you would have say an \\server\InfoPath network folder.
Within it you have a template folder, which they have read access to it and it holds your published xsn's
Have a DB folder for the Access DB so you can have the same path for everyone.
Then have a docuemnts folder. If you want you can have all of the forms submit to this location and as long as each the form name is unique they would all merge back when they went online and synced the folder.
Then a project manager could access them via the network and do the final submit or the users themselves could do the final submit, whatever your process.
The database, if it is read-only for the users would be fine too. It does not sound like they are saving to the database so you would not need to worry about it being merged.
That is my idea. You can send me an email if you would like to discuss.