A 45 minute "splash and dash" in the middle of the night at NAN is not very difficult with a bit of prior planning. The wind and traffic situation usually allows for a landing on 03 and take off on 21. However you must allow for the loss of ground speed in the descent, arrival and landing. Ditto for the departure and climb - say about 75 minutes to get to the first way point en route assuming the same flight plan track. Done it a few times over the years.
DFW is simply not reliably doable in the US TS season when you're planned to arrive at 1300. It's not easy to carry a tempo for 15 hours. Then there is BNE with a planned arrival of 0500 in the fog season. Who plans this??? With a duty period planned at 17:30, there's not much time to bugger about.