Help me understand naval focused countries

Playing as Byz right now in 1400, got to own all Asia Menor coast and all of Greece, with a stable economy (30 ducats/month), but my control of those territories is not really high, mainly because of proximity.

With other land focused countries I just spammed roads, but here I have doubts.

I understand more or less maritime presence mechanic and harbors, but my question is, should I build a road from (for example) Bursa to other inland locations in Asia Menor?

My current strategy so far has been to upgrade capital provinces to towns to be able to build docks and other buildings to increase harbor capacity, is it a good idea?

Also, how many ships should I use to increase even more maritime presence and prevent pirates?

Thank you in advance