I agree. The domestic to international connection at DFW should be fine. The SkyLink trains are frequent and reliable. You should have no issues with a 65 minute connection, especially if you're in First as you'll be off the plane quickly.

When arriving at DFW on the international flight the best advice is as above. Assuming you have lounge access then I'd remain in Terminal D until it's time to head to your gate for your onward flight. Gates do change frequently at DFW (I think I had 3 or 4 gate changes for my last flight from DFW) so probably best not to leave too early.