Playing as Canada is the best and quickest option so pick Canada, train up 30 cavalry divisions and disband the rest of your army. The Focuses should simply be rushing down to Swastika Clubs then after that it doesn't matter until you become independent. When you get your first 150pp pick fascist demagogue, there is no rush though so don't waste political power until you get around 45% fascist to discredit government and become fascist. When fascist and independent pick support the blue shirts and if you're doing "It's 1812 All Over Again" Achievement now is the time you go down "Support a Synarchist Baja" but i would recommend doing them in separate runs.
Preperation of Troops
After becoming independent send your 30 cavalry divisions to Britain to garrison the required states(DONT GARRISON NORTHERN IRELAND & VICTORY POINTS ONLY). Move your troops off victory points with British divisions in them, leave the allies when the troops arrive in the United Kingdom, justify a war goal on the United States & any other minor nation that the United Kingdom will guarantee, the baltic countries work great and when you successfully get only Britain to guarantee cancel justification on the United States.
Conquest of Britain
Declare war on the country that Britain guaranteed in order to "Order 66" them. Move your cavalry divisions to victory points and attempt to breakthrough and flank the British garrison. Joining the axis is fine since when they capitulate you will gain control over all states anyway and it ties up more enemy divisions.
Good luck from mcullin2!