victory road is a pretty good place
soulsilver and heartgold, it has the most trainers
Mt. Silver or the Pokemon league
probly at the pokemon leuge
Some people will argue with me but i think the best place to train is at the Pokemon lugue you can battle them over and over again
Victory Road and Mt. Silver. However, if you cant reach this places yet, I transferred mine across to my older game where they could train Pokemon their level.
Elite four is the best because they get better and better, and your Pokemon are equally matched up.
soulsilver and heartgold, it has the most trainers
I would definitely say bugsy's Pokemon gym in azeala town or ilex Forrest
The elite four
Route 45 is probably the best place.
find a place that has wild Pokemon the same level as it.
elite 4
ANYWHERE
An area with grass Pokemon would be best.
sky piller
probly at the pokemon leuge
Mt. Silver or the Pokemon league