At that time the East Indies were rather well defended. I could see the British taking some small islands and perhaps get control of New Guinea but Java, the Molukken (don't know the English name) nor Sumatra would fall, with the possible exception of Atjeh, but I can see the Dutch defending their colony with allot of success.
The only reason the Japanese could take the Dutch East Indies was because it was already crippled.
Batavia would also be the longest surviving Dutch holding. In the Molukken and Java I don't see the dutch getting kicked out.
Also if the Dutch time their incursion well, they could at the same time plan an attack on Malaysia and perhaps even do a 'Pearl' on the British in Australia.
But the hardest thing would be getting the Dutch into the war. The easiest thing would be having Wilhelmina merry a Prusian, but that would mean the Dutch would have a rather increased military capability, just because of the Prusian at the Dutch court. Which would also put South Africa in danger because then the Dutch would start to get the Afrikaners, or Boeren to follow them and make Africa more of a battle field.
This would also lead to the emancipation of the Flemish people in Belgium, because at that time the Dutch speaking regions were oppressed and with Dutch involvement in the war, that would most likely result in getting the Flemish people follow in the war against France and the UK.
It would also lead to Belgian Congo joining the central powers for 90% of the ruling class at that time was Flemish.
So I think it is safe to assume that if the Dutch had been part of the war because of a Prussian marrying Wilhelmina, the war would have been different. (Anti-British sentiments were high because of the resent Boer-war)
This would also depend on how the Dutch act towards their brethren. If they act as their saviours and make the Flemish people think they are equal or even better than the Walons, then I can see the Flemish supporting the Dutch rather fast, causing mass revolts in the Belgian army (this is enhanced because of the fact Flemish soldiers did not understand French and were not taught it, but were expected to understand their French officers)
Thus depending on at what time the Dutch enter and why (being it a Prusian with Wilhelmina or being it an attack on Dutch shipping's (which have happened allot!)), the Dutch could win the war for the Germans.
At the start of WW2 the Dutch army AND navy was a shadow (compared to the armies etc of the other countries) of what it was at the time of WW1. Also the Dutch fleet in the Indies (both West and especially East) the Dutch could harm the British, thus tying up British resources elsewhere.
In Africa the Dutch could with held of the Flemish from Congo and the Germans from present day Namibia and the Boers/Afrikaners, take control of the tip of Africa. Keeping certain pockets of British resistance at a few points, perhaps the cape or even in a few major cities, but overall control turned over to the Dutch.
If the Dutch however join the war because of attacks on dutch shipping's, the war would result in loss, and the Dutch losing all colonies, perhaps Batavia and few areas around it would be annexed but stay in effective dutch control, but they would also lose about half of their territory on the North Sea, thus resulting in an even more fierce WW2. It would also keep Flemish people suppressed thus a possible revolution or civil war in Belgium.