Taking your points in turn (!)
(1) Yes, you can find the SRD online HERE
(2) No issue at all to nick an SRD route from a suitably nearby airfield. In fact, if you do, you'll probably find integration into the system rather easier.
Most of the autoroutes are clever enough to use the SRD, so you'll probably find little change in your results over and above using your normal software.
... and yes, I know... Old habits die hard!