NO max miles as long as you don't exceed 6 stops. Transit don't count as a stopover and a transit also don't count as backtracking. Each stopover must be in one continuous direction (so no backtracking (for stopover) is allowed). Max 3 stops per continents. Unlimited segments. All SkyTeam airlines can use each of its own frequent flyer miles to redeem this award. It requires a very advanced planning and quite time consuming if you want to get the dates (or close to the dates) that you want. If you start booking now for a trip this summer, u will find it very difficult to get a hold of award seats especially Europe-North Amerca or vice versa. Watch out blackout dates from each airlines as well (for sure KE has blackout from July 20-Aug 20). Although using NW miles (for your case), don't expect to fly on NW as their award seats availability really sucks (mostly asia-america-asia routing).