What made the Dutch government (want to) accept Wilhelm II following the exile he was forced into after the end of WWI? I know the Netherlands was neutral during the war, but did their monarchy have some sort of closer relation to Germany's in that era? I know that Wilhelm II was first cousins with Czar Nicholas II and George V, but was there a strong Dutch connection there as well, or was it something from Wilhelm's father's side?
The Netherlands was one of the easiest places to escape to. Also because The Netherlands was neutral in the war. At the end of the war there was a severe threat of a revolution in Berlin and the German army superiors adviced the Kaiser to travel to their military headquarters in Spa, Belgium. From here basically the only safe route to flee too was The Netherlands. Wilhelm II also always maintained the idea to some day return to Germany and wanted to stay close to Germany if that oppurtunity ever arose. Untill he died he kept believing that the German Monarchie would be restored.
The reason Queen Wilhelmina of the Netherlands supported him coming to the Netherlands is pretty obvious. They were uncle and neice. Queen Wilhemina used to call him "Onkel Willy" (Uncle Willy) which says a lot about their informal/friendly relationship with eachother. The Dutch royals travelled to the German court every summer ever since Queen Wilhelmina was 10 years of age. Hence why both royal families were very close to eachother. Also a lot of Dutch royalty married German nobles which has strengthened the German-Dutch relationships over the previous centuries.
Near the end of WW1 lot's of German and Dutch diplomats travelled back and fort which is a good indication they were already planning to flee to The Netherlands. Because The Netherlands was also the stage of peace treaty negotiations the other countries reluctantly agreed to let the emperor stay there at first because it was a safe option to prevent him escaping to other places in the world.
What they didn't know was that he seeked political asylum in The Netherlands and within 24 hours that application was formalized, theoretically making him excempt from prosecution. Queen Wilhelmina even offered him Palace " Het Loo" as a gift for him to live at. But the Dutch government prevented that and after that Kaiser Wilhem lived in "Castle Amerongen" till 1920. Then bought his own house after that in Amerongen where he lived and was buried after he died in 1941 at "Huise Doorn" (House Doorn). Adolf Hitler made sure he wasn't allowed back into Germany ever again so his ideas of reinstuting the Monarchie died with him.
The Kaiser spend most of his days woodworking and chopping down trees which despite him being born with a handicap (1 arm shorter than the other) made a significant dent in the landscape/forest surrounding Huise Doorn.
Queen Wilhelmina was forbidden to visit him after the war as the head of state. But unofficial visits have happened.
Side note: Officially Queen Wilhelmina and Kaiser Wilhelm were never informed about the plans to flee to The Netherlands and it was all arranged last-minute by German and Dutch diplomats/officers.
To answer why he fled to The Netherlands:
Sources:
(Edit: some spelling/grammar, writing English wasn't my best subject in school).
(Edit 2: Formatting and 5 reasons).