Look again; Japan has a load of units to counter Persia with. If you don’t reinforce Persia with Russian units, you’re going to lose a chunk of US tanks on the cheap.
(edit) or at least, they will be at severe risk. Anyways, Russian reinforcement will probably be more of a “must” than a “maybe”. (/edit)
Another threat to keep in mind is the upcoming Japan stack next to Moscow. Combined with moving 4 Jap fighters from W Eur to the Persian sea zone, and bomber build, you’re looking at a serious capital threat. If you keep the threat in mind when you do your moves, though, it’s easily neutralized.
The major Axis threat at this time will be a defense of Eastern Europe. More on this in a bit.
Think about keeping a US carrier at the east US sea zone. That allows fighters to start on the eastern US sea zone, which gives them some useful range.
The Allies probably cannot afford the time to build another major Allied defensive fleet, which means the Allies won’t be able to maintain two heavily guarded drop zones. I would guess your best short term bet in terms of UK/US reinforcement would be to take one minor fleet to the Karelia/Archangel sea zone, and a major fleet to maintain a flow through Algeria. Japan’s multiple bombers could make that difficult in a turn or two, but the key thing to watch out for is to make sure the Axis fighters can’t hit the Kar/Arch fleet, which should not be too difficult as long as you don’t let the Axis get set up with a Eastern Europe defense.
More on Axis setup at Eastern Europe - if you get Jap fighters on E Europe instead of W Europe, the Jap threat to Moscow gets a lot nastier, as well as threatening the Kar/Arch fleet that maintains a flow of units to Europe. (If you have a major fleet at Algeria, you will need two turns to reposition it at Kar/Arch, so keep that in mind).
Although you have not explicitly stated it, your plan is no longer one to crack Germany any time soon. (Given Japan’s turn, I think that’s right.) It is now a grindish game, with the Allies maintaining superior position and economy, but with the Axis probably making major moves economy-wise esp. at Africa. Be careful of Axis development at Africa, and if you think it appropriate, you may consider a light US Pacific fleet in time. (Probably not, but it’s something to keep in mind.)
(“Be careful” doesn’t mean you can’t let Japan expand in Africa. Just don’t let Japan expand in Africa while simultaneously letting the Axis shift into a long game situation.)
If you ARE planning on trying to build two major Allied defensive fleets, you will need more US fleet instead of transports.
I would guess Russia should use more tanks on Caucasus for its build, instead of getting so many infantry. I recommend against attempting to fortify either Kazakh or Novosibirsk.
Cauc tanks - threaten India, Eastern Europe/Ukraine, Novosibirsk, and Kazakh. Russian tanks are very sexy right now, very in. 4 out of 5 dentists recommend them.