Must Part 91 pilots comply with runway departures marked as NA?
Other than flying a published SID or ODP with charted takeoff minimums, there are no other takeoff minimum requirements for pilots operating under Part 91.

If a Part 91 pilot receives and accepts a published departure procedure from ATC then they must comply with any minimums published on the procedure. 

For example, some SID's may show takeoff minimums with a runway listed as "NA" (the Aspen Seven Departure as KASE lists "Rwy 15: NA - Terrain"). If you accepted this SID then you wouldn't be able to use runway 15 even operating under Part 91.

But just because you can doesn't mean you should. Every pilot flying Part 91 should have a set of personal minimums.

Just a pilot interpreting the regulations though, not a lawyer :)