In my opinion if Germany is to advance to the A-A line and the Caucasus in 1942, SU must colapse completly, otherwise, even with Moscow, Leningrad and Stalingrad occupied, the soviets can keep retreating until the germans are streched flat out. In order for the USSR to fall like this, something catastrophic on the governmental level has to happen. Maybe with Moscow taken in the autumn of 1941, on the basis of somehow better german logistics, Stalin stays behind and gets killed. In the ensuing chaos, different factions strugle for control, the remaining Red Army desintegrates, the constituent republics run by local worlords proclaim independence and ask Germany for terms. The Generalplan Ost had in mind the anihilation of about 50% percent of the SU population, over a period of 25 to 30 years after the war was won. But the war is not won because even with the SU out of the picture, the "real war" begins. US and GBR are still fighting. In order to keep relative peace in the east, they could implement a policy of carrot and stick towards the locals. Rewarding some, while punishing others, they could turn the different peoples of the ex-SU against each other. As such, with the support of local colaboators and Axis allies, while keeping german troops just for the most important tasks, they could keep the partisan problem in check.
Japanese troops will enter Siberia and take Vladivostok
As I was saying before, with the SU out, there is no chance for Spain, Vichy and Turkey to keep neutrality, they will join the Axis or suffer the consequences. Gibraltar and Malta will soon fall. With fuel, truks and air transports available from the eastern front(no Stalingrad loses), Rommel might have enough supplies to reach the Suez. The turkish infrastructure is not great, but is enough to send a few german divisions to enforce the local Vichy forces in Syria and advance in Palestine towards the Suez. The british don't have enough resouces and men at that moment to fight in northern Persia, Egypt, Syria and Irak. With Axis troops present, there's a big chance the locals will rebel again. In this context, with fuel, truks and air transports available from the eastern front(no Stalingrad loses), I belive Rommel will have enough suplies to breach El Alamein and reach Suez. The Royal Navy will be forced to abandon the Mediteranean Sea, evacuating Cyprus in the process. With the Med becoming an Axis lake, supplies and men can easily be sent wherever they are needed in the zone. I don't know if Op.Torch remains an option, with just the western shores of Marocco available for landing, against strong Axis defences and the american troops still untested in battle. Even the vast resources of the US will be put to test. They are outproducing the Axis by a lot, but they will have to fight mostly over enemy ground, so most of their pilots will be lost for good, it could take years to remove the entrenched Axis forces from N Africa and the Middle east, with heavy casualties for both sides.
The air war over Europe will be a lot more costlier then OTL, the Luftwaffe now has the necessary fuel for training and the strategic depth to build more aircraft factories. The war will be conducted mostly by night as the day wiil be far too dangerous for both sides. Even with the introduction of the Mustang, the Luftwaffe has enough pilots to engage the bombers and the escorts. If we take the "Big Week" in consideration where the Luftwaffe lost control over it's own sky, we could see that even with fewer planes and poorly trained pilots, they managed to shot down according to wiki 357 USAAF and RAF bombers and 28 fighters with over 2000 allied air men lost in action. The Luftwaffe lost 262 fighters, from wich many were Zerstorer and Sturmboke but most importantly they had just 100 KIA. Even for the allies, i don't think a ratio of 20-1, wich in ATL might be even higher, is sustainable for long.
Adolf may order the construction in the east of plants for the creation of the new nerve agents sarin, tabun and soman, together with a strategic reserve of bombers and v-1 bombs, to be used as retaliation against potential british use of gas.