You don't need a VPN or any 'special' hardware to achieve what you want. An RDP link and having the correct ports forwarded in your router will allow access to you LAN from the web.
Or if you have an Android device or Apple device TeamViewer is the app you require, plus a solution to 'wake' the hardware remotely.
What you need:
1. WAN/ public IP address of your router (where a static IP makes things much easier).
2. Forward TCP port 3389 on your router.
3. Verify you're allowing RDP connections through your firewall.
4. Allow RDP connections on the local computer.
5. If the device within your LAN isn't 'always on' you'll need a way of waking it over the web. Search for 'wake on wan' or 'magic packets' for a suitable tool.
I uses this to connect from a Windows 8 Tablet to my server in the loft at home. I don't use it for file transfer, mainly due to my upload data throughput rate but, it will allow that too.
All the above assumes it's a Windows PC, with the applicable OS, you're attempting to access. Maybe assuming too much there...
Paul
Edited by deleted (Thu 14-Aug-14 16:30:37)