Well, that's basically what I do. Blitz until I've got enough provinces to produce everything I want (troops, agents, boats & war machines) and then hunker down into turtle mode and improve the quality of my troops and provinces.

For me, that is the fun bit. Having small, high quality armies defend their homelands against massive crusades (bloated by Hungarian zeal) or making surgical strikes against blitz factions/superpowers.

At the moment I'm playing as the Turks in Late, and I've only my GA goal provinces and a handful of others, but I'm having a great time enticing big crusading factions into attacking cannonades of serpentines and organ guns backed up by a small standing army of high-morale (Ribat level) Turcoman Horse, arquebusiers, Futtuwas, Muwahids, and Armenian Heavies.

Good times.

My next goal is to build an "ultimate" 1 stack army (including Janissaries and Hashishin) with a moderately-talented general (4-6 stars), and to see how far my boys can strike into Christian territory. I'm even gonna have some boats waiting in the Channel and North Sea to ferry them over (just in case they get lucky).