The first thing that you need to understand is that the Keystone Pipeline that they keep talking about in the news is actually just an extension for TransCanada’s already existing pipeline. The Phase 1 section of the pipeline (shown in brown on the map), which runs from Hardisty, Alberta, Canada - where the green tank markers are on the map - to Patoka, Illinois, became operational in June 2010. Phase 2 (shown in green) runs from Steele City, Nebraska to Cushing, Oklahoma and was completed in February 2011. Phase 3 (shown in orange) continues on from Cushing, Oklahoma to a point near terminals in Nederland, Texas. Oil started moving through that section on January 21, 2014. Note that Cushing has storage facilities for American-produced oil, which can be added to the pipeline at this point.
The only things that haven't been build yet are the shortcut XL Extention - also know as Phase 4 - that would run from Hardisty through Baker, Montana to Steel City (shown on the map in dashed blue), and a short 47 mile leg that runs from from Liberty County, Texas to Houston, Texas - for better access to more export terminals. The latter is already under construction and should be completed later this year. The former (the blue dashed bit) is the only thing that has been held up. You will note that even without Phase 4 the pipeline makes a continuous path from Canada to Texas.
There are several issues with the Phase 4 proposal, the most prominant of which is probably the fact that it would run right over the Ogallala Aquifer in Nebraska. The Ogallala lies relatively close to the surface, is already under massive stress due to overuse, and is the water source for roughly one-fifth of the wheat, corn, cotton and cattle produced in the United States. Needless to say, the last thing we should do is leak a bunch of heavy, acidic bitumen into it.
However, stopping the construction of the extension would not stop Athabasca oil from reaching market. It would just slow it down. It would also slow down the shipment of oil from the Bakken in the US (noted in the map by those tanks at Baker). So one of the real issues that you need to wrestle with is whether it would be safer to ship the oil via pipeline (though getting it further away from the Ogallala should be a priority) or to ship it in a bunch of rail-cars or trucks. It would be nice to just stop use of heavy oil entirely, but we don't have anything to replace it with at the moment. So - no easy answers here. And no, it doesn't matter that you personally don't own a car - think about how food, clothing and all the other products you use get here.
I also want to point out that those job numbers that keep getting thrown around are nonsense. As I pointed out - most of the pipeline is already in place and the pipe for the remaining legs has already been manufactured and imported. The majority of the remaining jobs would be short term construction jobs that would disappear once the pipeline has been installed. And if past practice is any indication, most of those workers would not be local to the installation area, so most of the money flows out of the local economies, not in. There would be no massive economic boost from building Phase 4.
Now that you should be more clear on what exactly the Keystone pipeline is, I will continue this in part 2 with a discussion of the Athabasca tar sands.