Pokémon Diamond and Pearl/Route 227

This is the last route between you and Stark Mountain. Even the wild Pokémon here will give you a hard time if your Pokémon aren't at least level 60 or higher. This is a great place to level up before you go to Stark Mountain if you feel that you're not tough enough.

Wild Pokémon
Note: the fully evolved Pokémon (i.e. Rhydon, Weezing) are levels 54-56. However, the first form Pokémon (i.e. Gligar, Poliwag) are levels 20-23.

New Pokémon Encounters
This is assuming you choose to battle all the trainers on the route
 * Meowth
 * Persian
 * Weezing (unless you've evolved a Koffing)
 * Hypno

Items

 * Charcoal
 * Zinc
 * Protein

Points of Interest
There's a house much like the Old Lady's Rest Stop in R/S/E that will heal your Pokémon. Handy to do before heading off to Mount Stark.