If Spain joins, it will be early. No idea how to get Portugal, but lets just handwavium some fascist leader takes over in the 1930's. We know what the USA war plan was at the time. The USA/UK will take the Azores, Cape Verde and other Atlantic Islands, perhaps even before a declaration of war in 1941. It also triggers the USA making lost Dutch Islands and perhaps French Islands "USA protectorates" as had been arranged beforehand. After the war, these Islands will only go back if the Islands support this in the 1960's or 1970's. The USA will build massive bases there for the cold war. I think Marshallese or Fed Rep of Micronesia type status is likely. A huge % of the Azores population lives near Fall River Mass anyway, so their life is easier if they have USA citizenship. Probably Dual with Portugal.
The USA likely does torch, but all the troops go into Morocco or even farther South into the West African Coast. The next step is almost certainly Spain, to prevent it from being an air/naval base for the merchant warfare. This will occupy the USA through end of 1943. Italy will not be invade, and I doubt we go too far into Tunisia. I agree with Wiking the USA is likely to just use Spain as the main front and it is too wide for the Germans to block entirely. Breaking over the French/Spanish border will be hard, but it is how the USA most likely gets into France. We then likely do Marshall plan for Spain and Portugal, but we are much harder on Italy who will be more punished like Germany OTL. And with extra possible soldier to stand against the USSR, we might be harder on Germany post war. We can use Spanish and Portuguese units with USA equipment instead of German units (ITTL v OTL). There is not logical reason we can't build say Leopard tank factory in Spain instead of Germany, since USA money likely pays for either one.