Red isn't even that hard, in HGSS or GSC. The hardest thing about fighting him is that damn Snorlax, and even then, it's not as bad in HGSS without Rest + Sleep Talk (I think that's what it had). It just takes a long time to get to him with all the gyms and what not. I think that's the tedious part. Training though? I have beaten him with Pokemon that just got to level 50. Nothing fancy.