Re: The most simple way is not mentioned here?
RDP is interesting, if it's supported [it's likely a smaller business has HOME versions of windows, which don't allow remote-in].
There is a VERY SIMPLE solution, however:
a) VPN login to corporate network
b) VNC server running on the desktop [you'll need to log in first and leave it logged in, turn off those annoying lock screens, etc.]
BUT... if you run Linux or another POSIX operating system chances are you have OTHER things available, too, like ssh, "remote desktop" via the DISPLAY environment variable, and so on.
VNC is probably the easiest (so long as you don't lose the login on the desktop)
and when it comes to outright performance, remote X11 desktops are probably as good as (or maybe even better) than RDP...
[I do not know if there's an open source RDP server out there for windows, but there MIGHT be one for POSIX systems...)
It's also possible, on a POSIX system, to use something like 'Tiger VNC' to operate on its very own desktop. I do this a LOT to test X11 applicaitons. Run vncviewer on the main desktop, run the test applications on the tigervnc's X server with a different desktop (usually loalhost:1). There's really no reason you cannot have that secondary desktop running on a network-visible IP address, and then you just need to be able to VPN into the corporate network to access it.