I thought I would just post this here as a bit of advice to folks like myself who know a bit about computers and networking but not really that much.
In the past I have spent hours trying to get AirVPN set up on DD-WRT, PFSense and OpenWRT - basically I spent hours and hours, ending up with something functioning (pfSense - thanks to the guide here) eventually.
After my pfSense box died, I bricked two DD-WRT routers trying to set them up again, and spend hours trying to work out OpenWRT.
Eventually I ordered a GL.iNET micro router. It took about 10 minutes to get it working properly behind my ISP router - wish I had bought one ages ago!
I haven't seen a lot of info suggesting using these routers but I can recommend them, especially for the ease of use.
If anyone knows of other devices which are mostly plug and play it would be good to get a hardware list for all the non-techies who want a vpn but can't set up more involved options.
The more of the internet that is encrypted the better as far as I'm concerned!