I expect the Soviets will certainly go in to Manchuria and southern Sakhalin - for the latter I assume the USA would give it back to them even if they don't actually take it. I doubt the USA would be too happy if the USSR moved against the northern Kuriles, in any case with the surrender sooner the USN may get there before the Soviets could. Likewise the USA will get to Korea sooner than OTL and the Soviets will be not so far south...perhaps the dividing line is the narrow waist of Korea rather than 38th parallel.
If the Japanese give up before the USSR declaration of war, I can see the USA tolerating moves in to Manchuria and Sakhalin but no more. After all the Soviets already have not followed the agreement on declaring war (was supposed to be 3 months after Germany gives up). The USA is already unhappy by summer 1945 with Soviets activity in Eastern Europe, for them to take the Kuriles, occupy Korea is a blatant land grab - no justification at all.
If the Soviets do try and grab what they did OTL after Japan surrenders, you may see US-Soviet and even UK-Soviet relations deteriorate even faster than OTL. If that happens might even see the British not sending those jet engines to the USSR, and this will seriously delay the development of the Mig-15 and Soviet jet aircraft.