In fairly short order got my two RPi's running with a PPP network in the remote/base configuration as planned for in the last post. Closely following the tutorials on http://rpi900.com made it fairly easy work. The remote RPi now has a network connection over RF 900 MHz ISM band (using the RPi900/DNT900) via the base RPi. I can SSH into the remote RPi without depending on Wifi or a physical network cable (on the remote radio), just the local 'base' RPi requires a standard network connection. At the moment my test setup just has my radios covering less than 50 meters and a few levels of my townhome. Much more testing and experimenting to follow.
The RPi900 tutorials call for rpirtscts (flow control) & dnt900 (line discipline software) , which were developed/tested on Arch Linux (I believe). Given that, I chose Arch Linux for my Raspberry Pi's OS (to keep hassles at a minimum.)
Not sure if it was due to initial poor configuration on my part, but I not was unable to get my dnt900's working with PPP on a basic load of (just) Arch Linux. When I jumped to NOOB (then booted Arch Linux), things seemed to go smoother for me. NOOB likely eats up abit more memory of the SD card on the RPi, but solved some odd PPP connection issues I could never quite narrow down. (Perhaps fodder for a future post.)
I've controlled my Arch Linux install setup here, and my RPi900/DNT900/PPP setup steps here. The entire Remote Garden Monitor project is also on GitHub Perhaps 10% of setup steps are specific to my setup, so buyer beware (this is not something you can just clone and build, but I hope it is of some help). I cannot stress enough that the tutorials on http://rpi900.com/ were invaluable, and nearly followed verbatim.