This episode is clearly talking about the same barrier, and it is established as being at the edge of the galaxy.
But that's exactly what I was saying all along - that it's always just "edge this", "edge that", and that this in no explicit way relates to a border between inside and outside. A galaxy in reality is full of (unmarked) edges between various parts; an edge between inside and outside is in fact the least likely proposition, because real galaxies don't have definite insides and outsides.
This is the reason why we are free to place the purple barrier anywhere we wish: because the writers' intention of having it separate the inside from the outside is contrary to fact, and not really supported by the fiction, either. Standard fare for science fiction where whatever science the writers know, it's either wrong altogether or then at least outdated.
And no, this doesn't change the fact that a sublight journey to the edge would still probably
be an amazing millennial feat rather than a two-century hop. On that we are fully agreed.
Btw...did Trek *ever* use time dilation as a part of the plot?
Apparently not, although it's a great way to wiggle out of speed-distance-time inconsistencies. Trek drives apparently make relativity a user-selectable option, but it's not as if it has gone away as a concept altogether.
Every hour they would run into some new hard-headed alien of the week.
Hmm... What can be done about a starship barreling forward at lightspeed? Ships at warp can be stopped dead on their tracks by collapsing the warp field with weapons fire (say, DS9 "Favor the Bold"), but a ship simply coasting insanely fast won't mind if her engines get damaged or destroyed. The hard-headed aliens could board or destroy her, yes, but stop or divert?
That's another scenario Trek never quite tackled. We have seen tractor beams used for capturing a target at warp (DS9 "Paradise"), but do they work on high sublight targets with lots of "natural", Newtonian-Einsteinian kinetic energy? How does one get a ship to large fractions of c anyway - can it be done with warp drives? (See ST:TMP here...)
Also, we never get a clear picture of how fast ships accelerate at impulse. Certain visuals suggest accelerations around a thousand gee, but when two ships maneuver next to each other, accelerations of less than one gee seem to be the norm. Does reaching 0.95 c take a minute, a day, or a year of running at full impulse?