--- Snip --- One of the major drawbacks to the IPIP tunnels used to transport AMPRNet data is that they don't work when you are using Network Address Translation (NAT). --- Snip ---
I disagree. As long as protocol 4 is forwarded (or just use DMZ) it works fine.
I use 192.168.1.X on all my normal stuff at home, and my Ras Pi running rip44d has a an address of 192.168.1.2. In my main home router I point DMZ to that address of the Pi. I use a single USB dongle and that interface has a 44.92.X.X address and connects to some Ubiquiti gear. Works fine.
http://www.qsl.net/kb9mwr/wapr/tcpip/rip44d.html http://www.qsl.net/kb9mwr/wapr/tcpip/