VS. Seeker
Here are some places to train ingame in Diamond and Pearl with the VS. Seeker.
Ace Trainer Ariana: Route 228 in the sandstorm area, way north right before the gate to the next area. She has an Ambipom Lv. 59, Chansey Lv. 59, and a Rapidash Lv. 59. If you battle her with the Vs. Seeker once you’ll get about 8,000 EXP. With a traded Pokémon that has a Lucky Egg attached, you’d get about 18,000 EXP. Talk about a lot of EXP!
Gentleman Jeremy and Socialite Reina: Route 212 at the bottom of the route right before you turn to go to the Trophy Garden. They are standing straight across from each other. Jeremy has a Chatot Lv. 60 and Reina has a Roselia Lv. 60 (only if you’ve caught Heatan already). They give out little more than 1,000 EXP. unfortunately, but the catch is that they both give $12000 which is the most from any trainer in the game.
Those seem to be the best trainers to battle if you need a lot of EXP. or money, which is always good.
Happy battling!
~Slix
