seeeeeriooouuusss ASB!
But, if it so happened that the US joined the Central Powers for whatever reason, I think an American invasion of Canada is pretty likely, as well as Jamaica and other islands in the Caribbean. Though I highly doubt that the US would want to occupy or could occupy all of Canada. It is the second largest nation on earth, after all, and very pro-UK.
I live in Washington State and have often thought that Vancouver Island would have a nice feng sheui quality as the Northwestern part of our state. So maybe the US gains some parts of Canada for their troubles, such as Vancouver Island, PEI or maybe the island portion of Newfoundland. I would Imagine Quebec could get some sort of independance (a la Turtledove in the big series of his).
But mostly I think it would tip the balance in Western Europe in the exact opposite way it did IOTL. US troops would get to W Europe (though the RN is very powerful, but the USN could protect convoys, especially with some U-Boote riding shotgun). Then they would provide the punch in the CP offensives. Brest-Litovsk still happens and the Germans get E. Europe, possibly fenegeling Ukranian independance, but most importantly send troops to the West. Along with the Amis this causes a French collapse.
Realistically, this is the end. The BEF heads back to England not wanting to fight on their own. They can negotiate a "status quo, ante bellum" with all the CP. France gets screwed, they lose several colonies in Africa. I'm thinking Madagascar, Mozambique, IC, Gabon to Germany; Guyana, Martinique, most of French Polynesia to the US. I agree that the US is not into land grab, but would want to be compensated for its troubles.
The Eastern 1/3 of Belgium, along with Luxembourg would be annexed to Germany. Germany gets the Belgian Congo, and tries do do something like its Mittelafrika plans. The rest of Belgium is possibly divided into Walloon and Flanders and maybe annexed by France and the Netherlands, respectively. But rarely do losing nations gain new territory. France pays some reparations. Britain and Russia pay none.
Europe is devastated. Germany might be able to get back on its feet soon, but the real winner would be the US. Britain has been humbled and is a little ticked by its rowdy former colony. France is pissed, but is in such chaos they can barely hold a nation together.
The stage would be easily set for WWII, possibly with a socialist/commie revolution in France, then alliance with the USSR.
But getting the US in the CP is pretty ASB....
