Alder. For strats, Agreed.
Don't use maple as a body unless you're someone enjoys very long sustain and would sit down most of the time when playing. Maple is extremely heavy but is a great option for those who enjoy tapping due to the sustain. And maple is kinda bright as well. Metal soloist - Maple. Blues guitarist - Alder.
But electric guitar-wise honestly, who really cares about the body wood? It's all about the pickups. Guitar body wood is like what recabling is to headphones. Very subtle effects. The only significant effect from guitar body types is sustain.
A maple neck has a good enough sustain.
Rosewood and ebony fingerboards have a longer sustain compared to maple fingerboards.
And finally, American? American strat/tele? Peh. Nothing special aside from the slightly better craftsmanship than Mexican Fenders which would barely be noticeable. If you want something of equal quality or close, get a Pre-1990's Japanese Fender which used some American parts in them. And personally, Japanese craftmanship is better than American craftsmanship IMO. Creativity too.

Not that I'm dissing American-made guitars compared to Japanese-made.
Back to the topic.
Enjoy long sustain and don't mind the heaviness - Go for Maple.
If not, pick Alder for the Strat sound.