Thanks!

If its advisable to stick with direct-like (rather than mileage-boosting) routes, would there be any advantage over collecting the miles on Delta's Skymiles to rack them up on Air France or KLM or even Korean Air's programs?
I have read (here) many gripes about SkyMiles not stretching as far as they should, but very little about the foreign company miles programs.

ALso, Air France flies CDG-NTE (Nantes), but I've seen a shiny fare (pretty sure it was on travelpapa.com) which included the TGV to Nantes (QJZ) instead. The fare quote stated 'French Based Carrier' but that Delta operates the air leg (obviously the French SNCF operates the train). I couldn't figure out if I could acquire the miles between Paris and Nantes buying the travel this way... Anyone know?

Again, super grateful, thanks!
e111