Hi :)

Here is all activities that you can do in the game.

Feel free to subscribe if you want to keep updated with my latest guides:
http://www.youtube.com/user/Khonziel?sub_confirmation=1

00:35 - Central Plains Area
02:30 - Continent Center Area
04:16 - East Ravine Area
06:18 - North Mountains Area
08:07 - Southeast Mountains Area

In order to reach level 50 in your Hovercar you need to have max rank in the Development Community, as shown in at the beginning of the video.

00:40 - Central Plains Area
02:54 - Continent Center Area
04:32 - East Ravine Area
06:52 - North Mountains Area
08:17 - Southeast Mountains Area

In order to reach level 50 in your Bipedal Robo Walker you need to have max rank in the Development Community, as shown in at the beginning of the video.

00:03 - Beginner: Sharpner's Protégé
01:23 - Intermediate: Yamcha's Challenge
02:44 - Advanced: Android 18's Wrath
04:11 - Legendary: Vegeta's Fastball

The strength that Gohan hits the ball is proportional to his level. If you can't hit the ball hard enough, it's because Gohan needs to get stronger. To reach 1st place in the Legendary (Vegeta), you need to have Gohan around level 120.