I only do EVs and have found some great spots
HP is sadly only at a low level on the driftveil bridge and duckletts
Attack is great because you can train either simply at route 1 or at dragonspiral tower for more exp (double grass outside is best)
Def is annoying because only wellspring cave is good, but woobats are annoying
Sp.Atk always go to celestial tower
Sp.Def either driftveil city surfing for frillish or go to Volcarona's chamber for some higher leveled claydols
Speed, route 3 water or route 14 water depending on desired exp
For pure exp, the stadium is best once a day, but audinos on route 14 might be your best bet