o this was helpful thnx
Vitamins won't work regardless if you have over 100 EVs.
I'm not sure if anyone's mentioned this, but all six of Morimoto's pokemon give 2 EVs in Speed. Also, the Triple/Rotation Simi-<suffix> battles in Opelucid also give 2 EVs each. These battle is good for leveling up while EV training.
my issues with route 4 are a) the constant sandstorm there, and b) the fact that route 1 also has 1 Atk EV 100% of the time with weaker pokemon.
i also have no idea how its never been mentioned though now that you bring it up. i think a route with guaranteed EVs in a certain stat deserves notice even if only so people know what options they have when EV training
For training HP, I go to Giant Chasm (specifically the Crater's Forest).
High level pokemon, most give HP EV's.
Info taken from Bulbapedia (http://bulbapedia.bulbagarden.net/wiki/Giant_Chasm)
Both types of grass feature the same encounter rates, albeit the dark grass contains higher level pokemon.
Clefairy-30% 2HP
Piloswine-25% 1HP 1Att
Ditto-15% 1HP
Lunatone-10% 2 Sp. Att
Solrock-10% 2 Att
Metang-10% 2 Def
Rustling grass:
Audino-85% 2 HP
Mamoswine-5% 3 Att
Clefable-5% 3 HP
Metagross-5% 3 Def
Definitely the best place to EV train for HP, in my opinion.