With a TSO146a GPS unit you are always able to fix your position legally (and continuously!), so the 2 hourly navaid fix requirement becomes irrelevant until the GPS goes Tango Uniform.
On a recent YSBK-YBNA-YBCG flt in CTA at flight levels in rather lovely weather I was denied IFR CLRNCE DCT BNA from a bit past past Maitland (edge of C into E) - so as soon as I could I cancelled IFR, "dropped" to VFR status, climbed 500' and went merrily on my way....That being said, some controllers have approved fairly lengthy DCT legs on similar routings.