Actually, if you want to have the Germans take Eastern US, you need to NOT do Sealion. You do everything like you are planning for Sealion: kill the Royal Navy, build up with lots of transports and men, tanks and artillery to go in them along with the usual AC build. Have Italy take and hold Gibraltar so Germany can make use of the naval base. Germany slips down from SZ 112 to SZ 91 on G3. If US sees it coming, with any luck Italy may have enough navy left to go clear out any blockers US may send out to SZ 102 or SZ 89. Then on G4, you launch from SZ 91 and attack SZ 101/Eastern USA.
On the Pacific side, Japan should gather their navy in SZ 6 and build as many transports/inf/art or armor as they can. THen Japan should try to hit SZ 1/British Columbia on J3 so they can go after Western USA on J4. Yeah, this will bring USA into the war a little earlier but not enough to make a difference. Normally, USA DOW on the Collect Income phase of US3. In this case, they would be able to DOW in the Combat Move phase. HOwever, they would still just have the 52 IPCs to spend during their Purchase Units phase.
One problem with this is if US puts any ships in the Sea Zones between SZ 6 and SZ 1. Then the Jap navy will have to attack them early to clear a path for their transports J3, which will mean USA might be in the war US 2 and have something like 77 IPCs to spend at what are now Major ICs (many more units). You would have to see just what USA does then to decide if you want to continue with this strategy. Even if Japan doesn’t attack the Western US, Germany could possibly still pull off an invasion of Eastern US, but might face more US units in a possible counter attack. Also, if Germany decides going after USA is just too risky, that big fleet could still be used for Sealion if you wish. Or, in two moves, it could be used to invade Leningrad for a big push into Russia.
Main problem with this idea is it’s kind of “all or nothing”. If Germany and Japan try this and are successful, then they will probably win the game for the AXis. If they fail for whatever reason, the Axis will be doomed. They will have spent their money on troops and equipment that were sent off to die half the world away and their home fronts will be much weaker than normal. All the other Allies will just have all sorts of fun with that.