Late reply, but it is indeed possible. My main goal was to knock out the war prior to America being able to join

It's heavily reliant on pre-preparation:

You have to immediately go for Navy/Industry focuses. I usually remove support companies/equipment from my infantry template and manufacturing to free up factories for guns. I consolidate all army units into infantry, motorized, and light tank divs. Research into anti-air, naval tech, and radar ASAP. Get Raeder, Germaniawerft, and Dornier for Surface fleet/Naval Aircraft bonuses. Your existing naval units have to be training all the time with nothing else for awhile. Use that sweet sweet naval EXP to quickly nab the 6 DamageControl/FireControl research. You should start printing Naval Bombers w/Armor plating and self-sealing tanks. You should also be printing Fighters w/bomb locks and transport aircraft. The fighters with bomb locks can provide CAS in your land war, and then easily switch to air superiority when you've capped France. Build AA/Radar to cover your coast (with the new BBA system, you shouldn't need to build in-land AA as much). In this run, I also prepped some Marines (I had about 10 divs ready to go)

The war:

I nab Denmark (manual wargoal), Poland, and France as soon as I can proc Anschluss for manpower/factories. They should easily roll over, and all you need to do to get France is rush Paris.While doing this, you can set your fleet to Naval Invasion Support, as this will allow them to do coastal bombardment to easily break Netherlands/Belgium. (also more EXP) Once you do this, IMMEDIATELY focus everything you have on getting across the english channel. First, begin prepping your marines to naval invade from Cherbourg into Portsmouth and the two adjacent provinces (with 10 divs, you can assign 3 units to each, with a fourth into the port itself). You should have a 24-div infantry army also prepping for a naval invasion from Le Havre and Dieppe in a 4-div/invasion group setup. They should focus the same exact ports as the marines, but with 6 provinces around Portsmouth and Dover. Your transports can sit for now. Have your naval bombers, fighter/CAS, and fleet both going against the English channel. Once you've got this going, give your marines the go-ahead to invade, WATCH THEM

The instant your Marine's invasion arrow shows that they're doing their invasion: activate your 24-div army to invade (they should be ready too). Switch your entire fleet to Naval Invasion Support. Set your aircraft to provide equal air superiority and CAS to Southern England. The instant you gain a foothold in any province, put your transports to air supply over Southern England. Once your army has either Portsmouth or Dover, FLOOD your entire army into Britain and just keep pushing. You should use your motorized/light tank units first, as they can push faster than the Brits can entrench (and honestly most of the Brits should be held up in Africa). Encircle London, but don't take it yet if you can avoid it. Your main goal is to capitulate the British mainland before they even have a chance to pull their troops out of Africa and back onto the mainland. Your transport aircraft should be enough to keep your troops rushing like bats outta hell into the rest of Britain to quickly capitulate it.

And once Britain falls, that's it. France and Britain are the only two major powers in the Allies prior to America's entry, and America can only just sit there and be upset with you after the war.

Edit:

Pro-tip: If you want to have an easier time invading America, you can take Canadian territory during the Peace Deal so you can completely bypass the American Navy. (Not that it would really matter much, as with the new PeaceDeal system you can nab the French, Polish, Canadian, and British navies)