Good guess.
The only problem I've fond in this movie is that almost everyone had saw this movie. Those who like Harry Potter also saw, and they know how to register a account on IMDb.
Then we get these threads.

My guess is he decided to follow the girl and tell her about the package he left on her doorstep in person.

I''m guessing he could have gone to Arinzona or New Mexico in the end.

OK, that whole plot was a little too sophisticated for this casual movie goer.
But, nice catch and a great answer!
New Board! (cross your fingers)
http://imdb2.freeforums.net/

Well, The film shows him turning to all directions and then he stops in the closing scene where the girl went having a very little smile in his face. So most probably he followed the girl.
after that who knows maybe she was married
, maybe she was not interested (although, from her behavior to him I believe she was)! By the way does anyone know who was this actress?
Don't know if you missed it (hard to if you paid attention) but in the beginning of the movie she had mailed divorce papers to the dude in Russia (guy in cowboy hat with hot Russian chick) who comments about it..the package had the same winged decal on it from her. Also, when Hanks character delivers package at the end, you see (on the overhead metal sign) at her ranch house the guys name is gone leaving only hers (had both his & her names on it when package is picked up at the beginning - when she's in the barn welding something)..this is mentioned in the trivia section and was to show she had gone thru leaving her husband and was alone (although, agreed, doesn't mean she'd be interested but that wasn't the point).

It's obvious, he goes back to the girls house.

Well, The film shows him turning to all directions and then he stops in the closing scene where the girl went having a very little smile in his face. So most probably he followed the girl. After that who knows maybe she was married, maybe she was not interested (although, from her behavior to him I believe she was)! By the way does anyone know who was this actress?

What's there to wonder..it's strongly implied after he sees the winged decal on the back of her truck and realizes she's the one (her mailed package) that saved his life he's going to go back to meet her.

I don't think he actually knew himself where he was going.
After Kelly moved on I think he just decided that he needed a fresh start somewhere else.