I have been using remote access software for many years from VPN's that I set up on my server, to UltraVNC, Windows Remote Desktop, TeamViewer, etc...
The simplest, and the one I continue to use daily is Teamviewer 10.
I service computers as a second job and use this to access a ton of systems from homeowner to businesses with 30 workstations and multiple servers.
If this is for you to access your systems there is no concern of permissions for specific drives/files etc.
But, if you are looking to allow employees limited access, I would suggest setting up a VPN.
Best of luck.