First off, how do you get to "the boss" as the person says, when he blocks your path, and secondly, where is Punk Girl Cecile (according to Serebii, the Protector is behind her, and I can't seem to find it)
To meet the boss, you have to know the Backflip and 360 roller skate tricks.
Head to the northwest corner, and a Punk Guy stops you. Impress him with your Roller Skate tricks; if you've learned the Backflip and the 360, he will let you continue north to meet "the boss". He has been waiting for someone who was born for beautiful skating. He believes that you have what it takes to master the most difficult trick, the Cosmic Flip, and kindly teaches it to you.
Source
Punk Girl Cecile is in the far west end of the Hotel, near the Route 16 side, and you have to use Rock Smash to get it. The Protector's location as per Bulbapedia:
Route 16 side, far west end, south of Punk Girl Cecile between a pair of cracked walls (requires Rock Smash)
Hope I Helped