I think the all-time E-3D record for Op VERITAS was 17.50, with the average being around 13.15. [But these missions did include AAR and I'm not sure what the non-AAR record would be]
My longest over 'stan (Jan 2002) was 15:40 - again due to the USAF E-3C not turning up on time. I believe that the longest E-3D sortie was the crew that was retasked on 9/11 to monitor returning civil traffic to UK after the US closed their airspace - probably PLE for a full toilet! Not sure of the exact time although I understand that 2 x AARs were needed. Good effort by all!