I used AF for my Round the World trip and here was my itinerary - NY (JFK) --> Tokyo --> Seoul---> Bombay----> Delhi ----> Paris--> NY

If you are wondering why it so short - well, I got the award for only 14,000 miles as I found a mistake on their website and they decided to honor it (this was two years ago). So I had to book the dates and cities immediately and with such few miles I didn't mind where I went. Anyways, I found out all the rules and here is what happened:

I wanted to do Seoul ---> Sydney but they said that wasn't allowed as I would be going North - South (instead of West - East). SO I had to buy a separate ticket for that.

Backtracking is only allowed for NY, Europe connections. For example if you want to go from Moscow - Berlin - London - NY, you could do that even though you would have to connect through Paris each time (and thus backtrack). I wanted to go from Delhi - Cairo - NY but the backtracking rule applied there as there was no way to go from Delhi to Cairo without stopping through Paris and since Cairo was not a European or North American connection, the backtracking was not allowed.

Trust me, the Round the World trip itinerary planning is not as easy as it sounds. There will be so many dates where an award seat won't be available, connections which won't be valid, etc. Instead of surprising your nephew, you might as well just let him decide which cities he wants to see and how long he wants to spend in each city. He will be surprised enough by the award and I'm sure he'll appreciate being able to choose his own itinerary.

Hope this helps....