Suggestion for upgrading VB6 app w/ good printing support

I wrote an application on VB6/Access for a retail shop almost 8 yrs ago. They are still using it, and now they are asking for changes/upgrade and want to acces开发者_开发知识库s from multiple locations + multiple machine per location. Earlier it was just one machine per location.

All location is going to run the same application except only the Inventory and customers are different along with app settings. Inventory should be able to move to different location.

I lost touch with VB & Access, also I would like to rewrite the app with open source tools.

I'm a web developer PHP/MySQL and can do html5 if necessary. I believe I can rewrite all the functionalities with PHP/MySQL but I am not confident in printing.

The main requirement of the app is, it should print as fast as it can, should support several custom paper sizes.

Also the database should work distributed environment, all location should be able to work independently as well as able to sync updates when connected.

1. What is the best thing I can do in this situation?
2. Would you recommend to create webapp, and do any desktop client only for printing. i.e VB in windows or shell script if linux? or any alternative?
3. Any recommended workflow/links for Database setup/mirroring?
4. Modify the existing VB application to run with required MySQL architecture?

Sorry to violate one question per post rule, but I don't know how to split it.

Lets start with printing.

1. You could do a print CSS file. But its not very precise. That would get printed from the client browser.
2. Generate a PDF. With that you could print from the server or from the client. Server would be a faster option. Although multiple printers could get complicated.

Database sync:

I would treat the central database as a separate app and devise rules for each location to sync to the central location. You may not need to share all data, and just replicating the data you get into complex replication rules.