It really depends on how far away you are from your other colonies and what resource you have.

If you're close to your capital and/or other colonies then a level 1 barracks and shipyard are all you will need for quite some time. As long as you have a barracks and shipyard you are able to garrison troops so its more time efficient to just train troops from your other settlements and redeploy them. If you're further away then you'll have to upgrade those buildings to at least level 3 to train your own phalanxes and ballista ships.

The next priority should be to build up your GR so as to stem corruption a bit. After that you'll need a warehouse level 4 to get the second level of the GR and if you're on your 4th settlement you'll need warehouse 9 to get the third GR.

While waiting for resources you should also invest in, at least, a level 4 wall (but with a garrisoned militia and navy attacks are low risk), a hideout and some spies to defend against intel ops, keep upgrading your tavern/museum and town hall to increase citizen growth, and when you feel like it build up your academy to increase research.

Once your income of resources (due to rapid citizen growth via the hall and happiness modifiers) out strips your demand then you can build a trade port and trading post to get rid of excess. You need a trade port to ship to your other cities, but you can still sell via the post and receive goods without it (which will also cut down the risk of attack).

To be honest with a hideout and spies doing counter ops for defense, no trade port, a military in house, and a high level warehouse from upgrading your GR the risk of attack is practically nill since the cost to do so would far outstrip the gains (low resource loading due to no port, casualties from defenders, high 'safe' amount due to warehouse).


You only need 1 workshop technically and it should be on your crystal island so you're not constantly shipping goods to it. However if later you want to build a second or third thats fine as well. All improvements are shared within your empire (or they will be when it starts working) and additional workshops will allow you to research different aspects at the same time. However it will be a PITA to ship the large sums of crystals to your workshop for use if you aren't producing it in the colony.