What would happen if person A made changes on a record and then person B went into that record and didn't have current information? Or what if person B made changes to the record too. Then when you try to "re-sync" them, which changes should be saved?

You could use local tables or have a look at this Sync Remote Database but you won't want to do this kind of thing with multiple people. Things are going to go bad, just a matter of when.

I would suggest upgrading infrastructure to improve the internet/lan speed instead