Can you replace the last part with до вокзалу, or is на вокзал the only way to say it correctly?
"на вокзал" means that you actually going to be on the station. "до вокзалу" - that you are going to be at the station.
на вокзалi... no?
where is something happening? - на вокзалі
where are you going to? - на вокзал
What's the difference between іду and йду? I don't get it.
I guess it is the same as A pan and AN apple.
Use it for a better sound.
Я іду [йа іду] Я йду [йа йду] - repeating й sounds not so good.
But it's not a strict rule.