Something like offline-sync or two-way replication?

Hi Fellas,

I've been asked to make a user-friendly front end to a fairly simple
database, originally I was looking at MySQL as the back-end but in truth
it doesn't really matter what is used for that component. They would
like to have a centralized database that various administrators can
access, etc, and have less problems with duplicating efforts -- most of
their work currently exists on paper. The database is not large, it
would take some time (many years) for the data to reach even a thousand
records.

Base actually makes this sort of work delightfully simple, a very simple
series of forms is essentially the most of it. The problem is, they
would like to access this remotely from various locations from a laptop,
and I can assume that an internet connection will not always be
available. 

So in essence, I'm looking for a way they can fill out a form, then
return to the office and upload their changes to a database. I don't
believe they necessarily need to access any data from the database
outside of the office, just to make changes to it when they return.
There are likely to be only around four people using this so efficiency
is not a high priority. Any suggestions on the best or perhaps easiest
way to do this?

Cheers!
SD