The only overlap between the TNG and TTN books is chronological; they're independent storywise. I'd actually recommend reading TTN, then TNG, then Destiny, since the TNG books lead more directly into the trilogy than the TTN books do.
But the basic chronological order for the TNG and TTN books is:
TNG: Death in Winter
TTN: Taking Wing
TTN: The Red King
TTN: Orion's Hounds
TNG: Resistance
TNG: Q&A
TNG: Before Dishonor
TTN: Sword of Damocles
TNG: Greater Than the Sum
Destiny
But the basic chronological order for the TNG and TTN books is:
TNG: Death in Winter
TTN: Taking Wing
TTN: The Red King
TTN: Orion's Hounds
TNG: Resistance
TNG: Q&A
TNG: Before Dishonor
TTN: Sword of Damocles
TNG: Greater Than the Sum
Destiny