Is it possible to invade the East Coast of USA/Canada if the Fascists won?

The initial invasion would be possible however any long term occupation would be very hard and logistically a nightmare. The problem is that to get reinforcements here would be difficult. Germany had a Navy, but not nearly the size required for a trans-Atlantic Invasion. For the invasion Germany would need at least as many troops used in Operation Barbarossa, put probably a lot more. The USA is much larger North to South then the USSR was during WWII. In order to transfer that many troops would take a huge amount of transports. If the Island hoping campaign in the Pacific is any indication of what it would take to do a Trans-ocean invasion, imagine trying to invade a country the size of the USA.

Also given the numerous cities along the east coast, where do you invade first? Boston, NYC, Philly, DC, Somewhere in Florida? Also given that your ships would have to turn around and cross back to get your reinforments, you are looking at an invasion with 8-9 million troops and leaving your first wave troops here alone for months

The answer is given by the history of European colonization of the Americas and by the tactics of the Revolutionary War and the War of 1812.

The strategic gateways from the Atlantic are:

1) The St. Lawrence Seaway that leads to the Great Lakes. From there, it's a short hop to the headwaters of the Mississippi. The Seaway also provides access to Lake Champlain which in turn leads to the Hudson river.

2) The Chesapeake Bay.

3) The Gulf of Mexico, and from there, the mouth of the Mississippi.

Fascism is the merging of government and business.

The Fascists invaded Washington D.C. 8 years ago, from the southwest.

If you are speaking of the Fascists of World War II, they were in the process of setting up stooges in the U.S. (the America First movement) and were working on an atomic bomb. If they had beaten the U.S. in the nuclear weapons race, they would have used them to force a U.S.surrender.

Troops would have been brought in by air. Hopping through G.B., Greenland and/or Iceland/ Nova Scotia and Canada.

The Germans were already training military governors to step in and take over existing local governments after the surrender.

It would have been very difficult. It probably would have come down to the use of nuclear weapons or a stalemate.

I suggest reading the book: There's a War to Be Won: The United States Army in World War II, by Geoffrey Perret

It would not be so easy because there is a lot of open water between Europe and USA. It would take large ships with a large fuel capacity to carry troops and armaments. And with all the open water they could see them coming from far away.