1. They might have attempted to conquer Alaska, based on their ability to control Siberia and the arctic regions of Russia. From there, they would have rolled over poorly defended Canada, from which they would have launched a massive invasion from the sparsely populated North-Western US.
Not a chance. The Germans had no intention nor the capability to conquer all of Russia, much less continue rolling into North America.
FYI, aside from addressing Versailles related greivances, Hitlers principal objective for the war was to sieze and colonize Eastern Europe extending to the Caucauses oilfields. The majority of the conquored peoples who didn't meet Germanic racial criteria were to be deported across the eastern frontier with the remainder to serve as menial labor.
Hitler didn't set out to conquor Western Europe. The only reason he attacked France and England was to protect his flank due to their unexpected war declaration following the invasion of Poland.
2. Using the historic grievances that Mexico has, especially over territorial loss in the 1848 war, Hitler could have encouraged the Mexicans to stage a massive military invasion from the South (something similar to what their illegals are already doing).
The Germans already tried this in WWI and it backfired. The Mexican army of 1941 was little advanced from their army that was so soundly trounced 100 years earlier.
3. Hitler could have reached out to the anti-FDR right-wing, the likes of Charles Lindberg, Henry Ford, Rev. Charles Coughlin, and their many followers who were influential in the America First Movement. He could have used the resentment that Irish-Americans and German-Americans had for Anglo elites who wanted to save Britain, a nation that many in both groups disliked (I am Irish myself, and I am aware about how many Irishmen resented going to help Britain. The Republic of Ireland made a conscious decision to stay neutral in the war to the very end).
He tried all those things.
4. Germany could have offered the South a second chance. -snip-.
5. -snip- A shared interest in race issues would have brought the Nazis and the New England Eugenicists together.
FYI, The Best thing Hitler could have done to keep America out of the war was to not to have declared war on us. He declared war on America, not the other way around. Why did he declare war on us? Because on December 7, 1941, the German offensive had bogged down in the snows of Russia. Hitler was desperate to get the Japanese to attack the Russians from the east and thought by declaring war on America, he could get the Japanese to apply pressure to the Russians.
Too bad for Hitler that the Japanese were determined to move south in order to seize the crucial oil and other raw materials in SouthEast Asia and Indonesia. Zuhkov had recently bloodied the Japanese nose and the Japanese highest priority in 1941-1942 was to secure sources of raw materials to the south. Stalin also knew this which is why he moved units from the east to take part in the Red Armys successfull counter-offensive in the winter of 1941-1942.
At Khalkin Gol on the Mongolia-Manchuria border, 1939. One of the most important battles of which nobody's heard.