Virtual Office

I just became MIS for a company that has almost all of it’s users connecting to the office over RAS and different ways such as PC Anywhere. The major problems are with backing up, connectivity, and syncronisation. Also most connections should be secure and through the internet. I know that there are a lot of different ways about doing allthis, but I need the advice of what works from who did it.
Thanks for the expert help that we all get here (or hope to get).