Locations To Train
(credit goes to Alexcalibur of Gamefaqs.com)
HP
Where: Route 201
Who: Bidoof (1)
Comments: Very easy for low level Pokemon, and Bidoofs are very easy to find. With the Pokeradar you hardly ever see anything else. Plus, killing Bidoofs is fun.
Where: Valley Windworks
Who: Shellos (1) Bidoof (1)
Comments: Just average. Nothing special about it, but it works.
Where: Route 222
Who: Gastrodon (2)
Comments: It gets the job done, but the Pokemon are a bit higher level. This can be good or bad, depending on your Pokemon and what you want.
Where: Surfing on Route 212
Who: Wooper (1) Quagsire (2)
Comments: You have to surf, but I'm pretty sure they are all that appear.
Attack
Where: Route 202
Who: Shinx (1)
Comments: Not really a great place, I recommend it only be used because it is the first place available. And the Shinx don't really come along that often without the Pokeradar.
Where: Route 212
Who: Kricketune (2) Bibarel (2)
Comments: It works too, much better than Shinx.
Where: Route 208
Who: Bibarel (2) Machop (1)
Comments: I think this route has less variety in Pokemon than the one above, making a bit better. I could be wrong though.
Where: Acuity Lakefront
Who: Snover (1) Machoke (2)
Comments: This is one of my favorite places to train physical sweepers. The only other Pokemon around here all give speed EVs. Namely Sneasel, Meditite, and Medicham. Handy.
Where: Lake Valor
Who: Seaking (2) Gyarados (2)
Comments: Higher level wild Pokemon, and you need to beat the elite four to get the super rod to catch these guys with. Otherwise fine.
Defense
Where: Oreburgh Gate, Left of Oreburgh City
Who: Geodude (1)
Comments: I think this is the first place in the game you can get defense EVs.
Where: Oreburgh Mine
Who: Geodude (1) Onix (1)
Comments: I think it is a bit better than the above one, and mere seconds away so why not use it. Still, there are better places.
Where: Ruin Maniacs Cave
Who: Hippopotas (1) Geodude (1)
Comments: Works fine, I don't think there's anything to run away from...
Where: Iron Island Mines
Who: Graveler (2) Onix (1) Steelix (2)
Comments: This one is pretty good. I like it, and you almost always run into Graveler.
Where: Snowpoint Temple
Who: Graveler (2) Onix (1) Steelix (2)
Comments: I think you need a floor other than the first for these to appear. You need to run from Sneasel and Golbat, or you can train speed too. I don't know why you would need defense AND speed, but whatever. At least these guys are higher level.
Sp. Attack
Where: Route 204
Who: Budew (1)
Comments: Pretty much the worst option here. But I think it is the first place possible.
Where: The old Chateau in Eterna Forest
Who: Gastly (1) Haunter (2) Gengar (3)
Comments: Pretty much the best option here. They are the only Pokemon that appear here. Haunter and Gengar only appear if a GBA Pokemon game is in your DS, and I think you have to be in the room with the eyes.
Where: Lost Tower on Route 209
Who: Gastly (1)
Comments: Up here because the only other Pokemon that is here is Zubat, which gives 1 speed, making this an ideal special sweeper training ground.
Where: Route 229
Who: Roselia (1) Gloom (2)
Comments: This is late in the game, and I think you might need the national dex, limiting this ones usefulness. But good for higher level Pokemon.
Where: Resort Areas pond
Who: Golduck (2)
Comments: Wait... this could be the best option here... I am fairly certain
Golduck is the only Pokemon that appears in this pond. I guess it depends on how often you can find Haunters and Gengars.
Sp. Defense
Where: Route 223
Who: Tentacruel (2) Mantyke (1)
Comments: I can't even think of an earlier place... this place is good though.
***Tentacools are the easiest ones, so just find a route that has them and you're set.***
Speed
Where: Route 201
Who: Starly (1)
Comments: Yeah, it is slow, but it is the first place in the game. They appear often though and even more so with the Pokeradar.
Where: Caves With Zubats and Golbats
Who: Zubat (1) Golbat (2)
Comments: There are tons of caves, and almost all of them have these Pokemon. So instead of picking one, I just wrote this.
Where: Victory Road Ponds
Who: Golbat (2)
Comments: I think only Golbats appear.
Where: Trophy Garden of Pokemon Mansion
Who: Pikachu (2) Pichu (1) Staravia (2)
Comments: I like this one, it is pretty easy. And remember that everyday a new Pokemon is put in the garden, which could add more to this list.
Where: Lost Tower South of Solaceon town.
Who: Zubat (1) Murkrow (1)
Comments: Why list this again when there are better options? Gastly also
appears here, which give 1 Special Attack point, making this a good place to train Special sweepers.
Where: Surfing on Route 228
Who: Poliwhirl (2) Poliwag (1)
Comments: I think only they appear. Supposedly it's sandstorming here.
Where: Acuity Lakefront
Who: Sneasel (1) Meditite (1) Medicham (2)
Comments: A good place to train physical sweepers, because the only other Pokemon her give attack. Check that section for those details.
Where: Route 225
Who: Spearow (1) Fearow (2) Rattata (1) Raticate (2)
Comments: There are a lot of them. And higher level.