Well, I'm about to enter the Eterna Forest from Floaroma Town. However, I think my team is too underleveled right now for me to even face off against Gardenia. My team right now is:

LV. 18
Trait: Torrent
Nature: Serious

Pound
Peck
Bubble
Metal Claw

LV. 17
Trait: Intimidate
Nature: Relaxed

Tackle
Double Team
Quick Attack
Wing Attack

LV. 17
Trait: Intimidate
Nature: Bold

Tackle
Leer
Charge
Bite

LV. 3 <--- HM Slave

Tackle
Rock Smash


But yeah, where's a good place to train before I face off against Gardenia? I'm aiming to train them until there at least LV. 22-23.