Re: "It was long suspected that there was a termination shock beyond the Kuiper belt where the solar wind would abruptly slow and perhaps produce a physical shock wave much like breaking the speed barrier does on Earth. In fact, that point exists and was measured but Voyager 1 and 2 have, in their separate directions, passed it without a bump."
This "termination shock" language we see that is oftentimes used by astrophysicists to describe cosmic plasma phenomena is possibly troublesome. Keep in mind that what we are measuring with plasmas is charged particles, their movements and the magnetic fields that these movements generate. Hannes Alfven -- the Nobel laureate who invented the magnetohydrodynamics (MHD) models which are now widely used to model these cosmic plasmas -- was adamant that there is no sense to simply applying mechanical terminology to cosmic plasmas. In fact, there exists quite a bit of controversy on the nature of these cosmic plasma models, insofar as Alfven distanced himself in his Nobel lecture in 1970 from the way in which astrophysicists were applying those MHD equations. Truth be told, the idealized MHD models which are now widely deployed cannot support electrodynamic phenomena. That would drastically distinguish the MHD models from the plasmas we are more familiar with down here on Earth (like your fluorescent or neon bulbs) -- which absolutely demand such electrodynamics to function.
See "Why Space Needs to Go Beyond the MHD Box" or "Importance of Electric Fields in Modeling Space Plasmas".
Re: "But the true edge is often considered at the Oort Cloud, which primarily ends at 50,000 AU, or 400 times the current distance that Voyager 1 is from the sun, and which may extend out faintly to 100,000 or 200,000 AU."
Note that the Oort Cloud is completely hypothetical (reporters really need to mention this!), and a necessary construct to support conventional cometary theory -- which has in recent years run into a number of observational issues. There is much reason today to be skeptical about our theories for comets, and the Oort Cloud cannot escape this skepticism.
See http://www.thunderbolts.info/pdf/ElectricComet.pdf or http://www.youtube.com/watch?v=34wtt2EUToo
Glenn Fleishman seems to know conventional theory quite well, but our models have not been working so well for this mission. Science journalism should also include a discussion of the under-performing aspects of our models, in addition to what is thought to be true. There have been, for instance, a lot of radio observations at 21 cm that have been done by Gerrit Verschuur which appear to suggest that the interstellar medium is not at all "cloud-like" -- but instead, at least in many places, extremely filamentary and even knotted. In fact, Verschuur has published a number of papers where he cites the existence of critical ionization velocity (CIV) redshifts emitted from these knots. Conventional theorists have largely failed to comprehend the significance of this claim, and have been rather dismissive of it. Observing CIV's associated with a knot within an interstellar filament would strongly suggest that the filaments are conducting electrical currents, as in a novelty plasma globe, for a CIV is what one gets when you slam charged particles into a neutral cloud of gas at an enormous velocity. In the process, the neutral cloud of gas is ionized. That claim, by itself, would seem to upend much of modern-day astrophysics and cosmology.
Verschuur is hardly some "fringe" researcher, and yet, since his results have not supported existing theories, what we tend to see in practice is that astrophysicists do not pay them much heed.
I talk routinely with astrophysics about these observations online and they are far too quick to reject anything which contradicts their textbook stories. The public should adopt a skeptical stance here, for this is not like the other successful sciences we are far more familiar with. We cannot really do experiments out there, and these MHD equations deviate in very important ways from our laboratory plasma observations. For a great historical review of how these idealized MHD equations came to be applied to cosmic plasmas, see David Talbott's historical review of Hannes Alfven's life story ...
The Plasma Universe of Hannes Alfven
At some point along the way of seeing lots of surprises, we should in theory come to expect surprises, and pay more heed to what they mean for our models.