The only problem with queueing up several things in advance is that if not carefully done, you'll have a negative cash flow for several years and can get yourself in a bind financially. Upon further thought, the first thing I usually do at the start of the year is take a look at cash flow, because that dictates what units and buildings can be constructed without bankrupting the country. Gotta have them florins.

I do already have provinces that are dedicated to either producing income or a specific unit. That does help in simplifying things.

Good comment about the generals. I find that I have to continually guard against low piety generals and provencial governors getting burned at the stake.