Must Part 91 pilots comply with runway departures marked as NA? I answered a recent question about the meaning of Takeoff Minimum NA and indicated that they do not apply to Part 91 pilots, but after thinking about it, I’m not so sure. I can’t find anything specifically saying that you can’t use runways marked as NA, although often the reason that the runway is not available would make using it a very unwise decision. e.g. terrain or obstacles. On the other hand an unmonitored ground facility when the tower is closed wouldn’t be an issue if you were using GPS to fly the departure.

The AIM 5-2-8 just says,

Pilots operating under 14 CFR Part 91 are strongly encouraged to file and fly a DP at night, during marginal Visual Meteorological Conditions (VMC) and Instrument Meteorological Conditions (IMC), when one is available. 

Part 91 §91.175   Takeoff and landing under IFR. (f) Civil airport takeoff minimums. excludes Part 91 operators by giving limitations that only apply to Part 121, 129, and 135 operators.

A a towered field with an operating control tower, they are unlikely to allow you to to takeoff under IFR on a runway marked as Takeoff Minimum NA but is there any restriction when the tower is closed or there is no tower?
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 :)