Put parenthesis around the prepositional phrases and underline the object of preposition, one sentence doesn't.

1. in Oregon, it can be quite rainy along the coast.

2. Everyone from the city and suburbs should vacation in the countryside during the summer months.

3. I have never seen a wild bear outside.

4. Johnson ran over the hill near the grocery store on his way to school.

() = prepositional phrase

{ } = object of preposition

1. (in {Oregon},) it can be quite rainy (along the {coast}.)

2. Everyone (from the {city} and {suburbs}) should vacation (in the {countryside}) (during the summer {months}.)

3. I have never seen a wild bear outside.

This sentence does not contain any prepositional phrases, regardless of the word, "outside," because nothing comes after it. For example, if said, "outside of Kentucky," then it'd be a prepositional phrase, Kentucky being the object of preposition.

4. Johnson ran (over the {hill}) (near the grocery {store}) (on his {way}) (to {school.})