I'm a fan of "time travel" stories in pretty much all methods one can craft a story. I think time travel works best in a visual medium such as movies, television, or comics so you can see the elements of the past or the future in an interesting way.
If you enjoy time travel stories as well then chances are we've enjoyed a few of the same stories over the years:
In BACK TO THE FUTURE a flux capacitor, which is what makes time travel possible, is installed into a Delorean sports car. The steel construction assisting in the process, and the Delorean giving the time machine a touch of much needed style.
In SOMEWHERE IN TIME Christopher Reeve uses a tape-recorded message to place him into a trance that has him traveling in time basically in his mind (although it feels real to him and the audience).
In 7DAYS alien technology is reverse engineered so that a single chrononaut can be sent back seven days in the past and change the world for the better.
In each of these examples the writers remembered that just because a device sends you back in time that same device doesn't necessarily move you across great geographic distances as well. the Delorean can actually drive, or fly in later sequels, but most of the time a time machine is stationary.
In Back to the Future the doc talks about going back in time to witness the signing of the Declaration of Independence. He'd actually have to operate the Delorean (or train in 3) from California to Philidelphia in order to make that happen.
Reaching 88 miles an hour will propel you back in time, but not across the world.
In 7 Days Mr. Parker (the Chrononaut) climbs out of the pod that he uses to navigate the time stream and he has to call in back to base and say "conundrum" in order to let them know that there's been a disaster and he's traveled back in time. They have to come and get him with some sort of transportation.
If the disaster is across the world, there needs to be more transportation that takes him there - such as to a submarine under the sea. The pod only goes back in time.
There is a lot of time travel fiction that ignores this rule. The trailers for LOOPER seem the be the most recent. Of course, I haven't seen the movie but it looks like a very strong character drama with a bit of action and scifi thrown in to make it interesting.
My guess would be that the technology will not be explained to the viewer (it rarely is in this type of movie - my favorite attempt is in TIME COP: "The technology is explained in the binders in front of you, you won't understand it any better than I did."). In the trailer, and in fact the basis for the entire story, we see urban city mobsters transporting people who need to be assassinated back in time to an "out of the way" place such as a farm or a river bank.
When time and space are both traveled by a time machine it always bothers me and it causes me to have less of an ability to "suspend disbelief" that is often required to enjoy such movies. I hope it's not very noticeable in Looper if at all.