@snoil If playing a KGF, bring everything to the Atlantic. If going KJF, bring everything to the Pacific. I play a KGF probably 95% of the time.
In most KGF games as the US, all you need to build is 1 carrier US1. Other than that, it’s all transports and land units. Sometimes you mix in a plane, but that’s a luxury buy. If Axis is investing heavily in air and naval units then more US navy is definitely needed. The priority is always taking and occupying land. Owning land is what gives you income to build more units. Water is worthless.
So, since land is the priority, then land units are the priority. Land units are the most efficient on land. Ships are the most efficient on water. Planes are less efficient but more flexible on land or water.
So you want to be building as many land units as possible. The large majority of these are going to be infantry because they are cheap so you can buy more of them. As the US, you have a logistics problem getting those land units somewhere useful, so you need transports. To move your transports you need surface ships like carriers with fighters, destroyers, cruisers, battleships to protect them.
Pound for pound destroyers are the best unit for protecting transports. Carriers with fighters are good too because the fighters can attack on land. Cruisers are alright, but over-priced. Battleships are situational and not ideal for an Atlantic fleet. Where I use a battleship is when I’m facing multiple fleets.
For example, as Japan if you are facing a UK fleet and a US fleet, then a battleship is pretty good because it gets a free repair, but for the most part they are just too expensive.
With the US you want to be up to around 7 or 8 transports by the end of round 2. After that reasonable people disagree on how many transports to have. I usually get up to 11 or 12. If the US doesn’t have France it’s 11. If they do, it’s 12. If I’m doing a Med shuck I might get up to 14. Some people keep it at 8 and build bombers.