8 transports sounds great but that would take many turns to set up if you are buying units to defend them right? Also, I would still be leaving Japan alone. I guess you could use Africa as a way to challenge Japan via India. However, once the units land in Africa it would take them 3 turns to arrive because of the mech. inf. ability supported by tanks.
One of my friends had an idea of using a conveyor belt to take Norway from Eastern Canada, then building an IC there. Norway would be much easier to hold and could act as a staging ground to reinforce Russia. If you use Russia’s lend lease ability, this may allow them to throw more resources towards Japan and stall their advance.
It’s hard to give you advice if we don’t know what optional rules you are playing with (lend lease, mech inf?).
As for the USA transport chain (called the “shuck”), Fleetwood is correct, you want to build up to about 8 transports.
You should never need to buy any more than 1 AC for protection (if you go North eg the Baltic, you may not even need that). So for starters, here is a buying strat for ya
USA: 1 ac, 1 tran, 6inf (or 3 inf 1 arm)
USA2: 2 trn 3inf 3 arm
USA3: same, 2 trn plus gear
USA4:1 trn, plus more gear (should be 4 inf 4 arm)
from then on you keep buying inf/arm mostly, and you consider buying up to 2 more transports to create more of a threat. If end up with a 2/2 shuck to Europe (either through the Med or the Baltic), you will need at least 5 transports to get 10 land units (say 7inf, 3arm, which equals 36 ipcs, which USA should always be able to afford) to Europe.
Re transport buys, the key principle is always have enough transports to get the men you have to Europe/Africa…until you reach 8…at which point you should be buying mostly inf/tanks plus occasional fighters, and maybe 2-4 more transports if you need them to project a whole lot of troops to one location.
The point of this strat is NOT to march your forces through Africa to Persia etc. If Germany plays really conservative you might have to do this, but this shouldn’t be your goal. Your goal is to first secure Africa, but more importantly you want to threaten and eventually conquer Europe in conjunction with UK forces. For example, it may be possible to land 1-2 in Western Europe, in that case you may be able to land figs there as well. Since inf defends at 2 and armor at 3, and since UK and USA can COMBINE forces, whenever you have the chance to force Germany to attack you instead of you attacking them, you should consider it.
Either way, once you get up to 8 transports, you should be able to threaten a landing on Western with…
10 British land units (with 5 transports)
16 American land units
3-4 American fighters
Now to defend against this, Germany can either stack Western or keep a ton of force in Southern/Germany to attack any landing on Western. Either way, it should be hard for Germany to do this and get any offensive going against Russia, so Russia should be able to press into Eastern Europe and get rich on those ipcs. Try to get Norway for Russia too…you do this by taking karelia with UK on Turn 1, and then using a Russian tank to blitz in on Russia2.