I thought "andaria" was a synonym with "go". I've heard it used like that in my Brazilian neighborhood.
It is not a synonym, as "andar" means "to walk" (implying you are specifically going on foot), and "go" (ir) is a more general verb.
He would go to her house. = Ele iria para a casa dela.
That's not strictly true. People say: "andar de pe", "andar de bicicleta", "andar de carro" etc. In that sense, it means "go" more broadly
I do agree. My translation was : I would go to her house. It wasn't accepted. I think that andar means go not walk. Caminhar is to walk
Mas "I" = "eu", não "ele".
For the listening exercise: é impossível ouvir "a", o artigo - desaparece totalmente no "para"!
Exactly. That's how natives pronounce it! The same way we can't hear the "T" in "what to do". Here we have linked sounds.
However, we always use articles with "dele, dela, deles" and "delas", so it is wrong to omit it here.
In spoken Portuguese, we usually say: "pra casa dela".
Why "para a"? Couldn't ele andaria a casa dela work?
"Para" or "até" are the most common words used after "andar" to indicate a destination.
"Ele andaria para/até a casa dela."