Well, you need coins to continue drawing cards. You get coins almost exclusively from fields (hops/wheat).
To get a field, you need to play a wooden house, which gives you a chance of gaining a field or lumberyard.Only way to get a wooden house is by building lumberyard, which gives a chance of gaining a wooden house or pier. You can only build a lumberyard if you have trees, and you can only get trees, which you get from island card. The only way to get island cards is by playing piers, however, only some island cards have trees.
Therefore, the optimal order would be house -> lumberyard -> pior, because fields and island cards don't grant new cards, it doesn't matter when they are played.
