First of all, there would have been no "truce" with Russia. It seems everyone has forgotten, Hitler's entire justification for taking Europe under his control was that he didnt have the resources to fight Russia. He may have used other excuses to the world in the beginning, but taking out Stalin's Russia was his priority. He saw Communism as the ultimate threat and was determined to stomp it out. Britain was certainly a roadblock, but Hitler never much wanted a war with them anyway. What he wanted was
1) All of mainland Europe under German control, and access to all the resources.
2) Either a treaty or some other form of controlling England to keep them from being an aggressor and/or launching pad for aggressors, requiring him to fight on 2 fronts. He was more than willing to use force, but didnt want to if he could get away with it. Luckily for Britain, Hitler decided to stop expending resources trying to conquer them, when it wasnt necessary. He switched his focus to his real objective, Communist Russia, and left the Western Front as a holding action to keep the British off the mainland. He decided he could afford the resources after all, and Britain wasnt much of a threat away from their own shores.
Russia would have done just fine without us or our Lend/Lease. Eventually. They would have done much better in the beginning if Stalin werent such a paranoid delusional. He saw conspiracies in every shadow and whisper. Most of his experienced military were executed because he saw them as a threat. So while Germany had experienced pilots and troops, the advantage of the technological advances that came from using the equipment in battle and making it better, etc., Russia had outdated equipment and poorly trained, inexperienced people. The only thing that really saved them was Mother Nature. The Russian winter gave them the time they needed to set up manufacturing centers far back from the front lines and begin mass producing tanks and planes and guns to fight the Germans. It also gave them time to collect their army, train them into some semblance of usefulness and begin pushing back. It certainly helped when the US began putting pressure on a Western Front that Hitler hadn't planned on assigning any real resources to. But given the relative size and population of Russia vs German occupied Europe, I'm not sure it would have mattered. It would have been longer, and very ugly, but I'm pretty positive Russia would have eventually kicked the snot out of them.
