Where can I lvl up my pokemon after beating all gym leaders and trainers?

Question

It is for Heart Gold and I also wanna know if you can fight the gym fighter repeatedly after you get their number.....

Answer 1

Yes you can fight the gym leaders repeatedly you can also train on the elite four and red

Comments

So after I beat Red I can fight him as much as I want or only once??

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As much as you want

Answer 2

When you obtain all the gym leaders numbers, you're only allowed to fight them unlimited times during certain times of days.
For example: For Blaine, you can only fight him Tuesday Noons, so depending on your Pokegear/Nintendo DS clock, you can only fight Blaine on Tuesday, at noon.

Answer 3

Yes you can rematch them as much as you like as long as you have their pokegear number and on the right day/time.Although you can only rematch the gym leader once every day.