I spent a long time in Cubeo. I got most of the rank needed for my Cutter there. I had my Anaconda setup for half cargo and half passengers and did untold number of missions looping around the nearby systems. I'll totally head back there one day as I am allied with tons of minor factions in the area.
It's funny. Ranking up the slower way by doing missions in core areas does pay off afterward because now you have the REP in these large systems when you are done. Glad I did it that way.
Since you are a fellow Aisling Duval system lover... You should check out PIRA/Kuo Port. Kuo is an outpost that offers up some VERY lucrative Boom Time Delivery Missions that are perfectly suited to the Python. 180 tons on average and the payouts range from just over 6 Million to just under 10 million for a single jump A to B drop.
Yes I agree, there are some great high profit systems close to Cubeo especially once allied with the local Imperial factions which are ideal for medium sized ships and in particular the Python. I must visit Pira again as sometimes the 6-10 million single jump missions in Lambda Hydri run dry. Very useful after an expensive spell of ship buying and outfitting!