Hitler land grab WI

What if Hitler went after the Polish corridor before the Sudetanland(sic)? Would the allies have allowed that, and vowed to protect the rest of Poland, or Czechoslovakia?

Very hard to say. My best guess is that if Hitler would have played the same game for Poland that he did in OTL Czecheslowakia, i.e. helping the suppressed German minority and making good on injustices by Versailes then the allies might react the same than in OTL Cz. (Peace in our time and all that) The reaction of the Western States would depend a lot on whether Hitler would work together with the USSR or not. As long as Hitler looked like a good bulwark against the Bolshewists he could get away with a lot.

Hmmm, if Poland goes to war there is the added danger that Czechoslovakia will too, and the position of Italy is less certain in 1938 than in 1939 due to much anger over the annexation of Austria

Grey Wolf

Hitler called Chechoslovakia dagger aimed at the heart of Germany so I doubt he would go after Poland before taking care of CS.

Treatys

France had a treaty with Poland and England had a treaty with France. If Hitler attacked Poland he was at war with Poland, France, England, Czechoslovakia, and a bunch of other countries. He had to get the French and British to abandon their treaty with Czechoslovakia to get the Sudetenland.

Uhm the western-polish "treaty" was made in spring 1939 after the grab of bohemia-moravia... The poles, in the sight of the west, were a ragtag bunch of unimportant slavs, much as they were in the eyes of the Nazis. The poor right-wing government of the colonels offered the drawbacks of dictatorships without offering its usual advantages, in the west's way of thinking. The only reason they "fought for Danzig" was because it was a convenient place to step in and fight, since the war was now seemingly unavoidable. To think they cared for Poland is a huge mistake.

In fact, in 1938 its HITLER who had a non-agression treaty with the poles. Aside from that, there was the little entente, which proved its ineffectiveness in the sudentenland crisis.

If Hitler had gone for poland first, imo, he'd have gotten away with it, probably would have gotten the 1913 borders on the promise to respect the sovereignty of the rest.

However, he'd need to pull an ace to get both that and the sudentenland later... most likely, it would just be swapping freebies; later down the line, the Czechs would be ready to fight, and the west as well.