Hi Pambele,

Welcome to the Forum.

He also had the support of the crowd, with his hometown of Philadelphia being just up the road.

 Note the comma before WITH.  I never know when to use a comma before with and when not.  Can anyone explain the difference? 

It depends on how 'tightly coupled' the will phrase is to what precedes it. In other words, it depends on how important the phrase is to the overall meaning of the sentence.

eg He surprised her with an engagement ring.   He surprised her, with an umbrella in his hand. 

eg He fell with a dozen eggs in his hand, but none of the eggs broke.       He fell, with a book in his hand. 

Another way to look at this is to consider that a comma represents a pause in speaking. So, put a comma if you feel that you would pause.  However, I realize that this can sometimes be difficult for learners to judge.

Finally, there are cases where the same sentence may or may not use a comma, depending on the meaning you wish to convey.

eg He went to the movies with Mary.  This sounds like they were on a date. Mary is an important part of the 'sentence-story'.

eg He went to the movies, with Mary. This sounds like he went because he wanted to see the movie. Mary just happened to accompany him.

Best wishes, Clive