For early expansion as Hungary (VH/VH), I tend to build :

1. Church - to prevent Pagan Magician, to produce priest, to enhance piety of General (well, as there are so many pagan regions around Hungary)

2. Road - for faster movement of armies, generals, priests

3. Farm - to prevent traits of bad taxman, to increse income

4. military - to produce armies.

*For Budapest/Bran (starting Hungaruan regions), I will push military buildings forward.