If Jake wasn't at home with Octavia then he was at work at the photo studio. When he wasn't there he went wherever the camera took him. Madison Valley had definitely been a bit crazy ever since he got there. Between the snowmen, Valentine's Day stuff and just the general craziness, he was glad to have a day to himself. Even if he'd rather be off with his girlfriend, but she was working.
He's checking the world out through the lens of the camera when he sees her walk into the park. Someone that he didn't know that well. Actually, it was probably someone that he'd talked to on the net, but only once.