Well, as we've already discussed via ICQ, Scott, the only way to achieve success as Naples, at least in SP, is to expand immediately at all cost, declaring war on the pope on May 1419, when I receive my first diplomat. The pope always enters on an alliance in June, so I can start the war having the upper hand.
Take lots of automatic loans, mint NO coin, only invest in stability. This is because I won't have enough income to be mint
, so I'd only have inflation and no money. The plan is to be bankrupt just after the war, using the money from the loans to build a fleet and TCs on the new provinces of Romagna and Marche. After that...

Take lots of automatic loans, mint NO coin, only invest in stability. This is because I won't have enough income to be mint