Jedi Tricks

I've been thinking about two statements from the original Star Wars trilogy that used to not make sense to me.  One does now.  The thing about the original movies is that everything felt so close.  The travel from Tattooine to Alderaan takes only a few hours.  You forget that this is taking place over trillions of miles.  It was only recently that I realized what Darth Vader meant when he said that the Force was stronger than any space station that could exist.  He then force chokes someone.  In the next movie he force chokes someone he happens to be talking to on a well for better terms let's call it a space phone.  He then force chokes that person.  It was then that I realized, he could do that over trillions of miles.  And it was one of those sit back and say "whoa" moments.

The second statement is when the jedis say that if you strike them down they will become more powerful than anyone could ever imagine.  Maybe I don't understand all the rules of being a force ghost but it didn't seem like they had an overly large area of influence except amongst their own people.  Maybe I'm missing something.