The ability to work remotely (ie: not in the office) from your computer, laptop or even a tablet/smartphone, is pretty much a basic requirement these days for any corporate network. Cloud-based applications are making this easier than ever for the simple reason that most good cloud applications have been written from the ground up to be used remotely. It's kinda the point of the thing after all. There are certainly some 'cloud' applications that are nothing more than traditional applications being shoe-horned into the cloud by software vendors desperately trying to stay relevant to the market, but even those are fading away as fundamental rewrites bring these vendors properly into the modern age.
But what about non-cloud apps? The cloud gets a lot of press these days but the fact remains that a huge amount of corporate systems still run 'on-premise', and need to be accessed remotely. At the risk of gross generalisation there are two main methods available to facilitate remote access to on-premise systems, and the choice of which to use may largely depend on the application itself.
Virtual Private Network (VPN)
A Virtual Private Network (VPN) is a secure connection that you establish from your computer, via the internet, back to your office network. Once you connect your VPN (simply by clicking an icon on your computer), your computer will be joined to the office network just as if you were physically in the office, albeit slower. In most cases you will already have everything in place to start using a VPN, it may just require a small amount of configuration to enable the relevant features. VPN's are cheap and effective for things like accessing shared files, but they do have their limitations, mainly due to the fact that, going via the internet the way they do, they can be slow. Certainly a lot slower than if you were actually in the office. In practice this means that some applications (I'm looking at you, MYOB) will not only be too slow to use effectively, but can also pose a very real risk of corrupting your data.
I'm using the phrase 'Remote Desktop' to cover a range of specific technologies that all basically do the same thing, in that they let you remotely control a computer that is back at the office. Think of terms such as 'Citrix', 'Terminal Server', and 'LogMeIn' and you might know where we're going with this. A remote desktop has the advantage of only having to transfer via the internet what is displayed on the screen, and your keyboard and mouse clicks in return. All of the actual 'data' and 'processing' work stays on the computer back at the office that you are remotely controlling. This is the ideal method when you need to use apps that won't play nicely via a VPN, and also in some instances when you need a little more control and security around your corporate systems and data. Some methods of Remote Desktop don't need to cost much to setup, however there may be some requirements for your situation that mean you will need to commit some money to getting the relevant technology in place.
The final point to note with any of these remote access solutions is that the quality of the result can be largely dependent on the speed of the Internet connection between the remote worker, and the office network. A slow point somewhere in there can unfortunately result in a frustrating and unproductive experience. That point aside though, remote access to on-premise systems can be a massive productivity gain, and is well worth investigating if you don't already have something in place.