The Ice path never showed me any troubles. I never had to experience it as a child and trying to get through it, but in HGSS, I went through it no troubles. I even got most the items out of it.
As for frustrating, Morty's Gengar. Miltank is difficult but Gengar would OHKO my entire team with Shadow Ball. Biff (my Pidgeotto) was the only one who could survive the Shadow ball being immune to it. So, setting up a strategy and inching my way through his HP, I finally defeated him.