If you head West to the gate, you can get a look at a model bridge and hear about the Tubeline Bridge, which leads further West from here.  Unfortunately, you can't cross the Tubeline, as it's currently undergoing testing.

Do whatever amount of training on Route 9 you feel is appropriate, then head back into Opelucid and heal up so you can go have a try at the gym.

As you enter, you'll be approached by the Fresh Water guy again- after giving you his gift, he'll point out the two gigantic dragon statues in the gym, but unlike in Black and White, this time you don't have to move the bits of the dragons around- instead, you're trying to reach up to the head of the tall dragon from the head of the long dragon.  Drayden waits there, on the head, though other trainers are located on the other limbs.

Fresh Water Guy tips you that Dragon pokemon take added damage from both Ice and Dragon moves, then steps aside to let you walk towards the first statue.

Climb onto its back, following the line of lights in the floor, then head North along the dragon's spine to its head.  This will take you to the tailfin of the vertical dragon, where you will fight your first Gym Trainer here.

Battle: Veteran Lucius (3680 Poke)
Opponent: Fraxure Lv 46

Return to the dragon head and the forward direction will light up.  You must then choose right or left- depending on whether you feel more prepared to face defense specialists (Left side) or offense specialists (Right side).