There is a very interesting article about the route in May's (I think it was May's issue) Airways magazine. CO, Boeing and the FAA worked on the planning of the route, including visiting the various alternative landing strips on the route which would used if something went wrong on the flight. However as regards the flying of the route I can't remember it mentioning any restrictions. The only extra provisions made for the flight is that 2 whole flight deck crews are carried, upon entering Russian airspace it has to climb as they use Metres while Canada/USA use Feet and the crew have to be very careful in monitoring the fuel temperature as it is so cold going over the polar cap, that the fuel in the wing tips is actually in danger of freezing!
Check out the article though as it tells you everything about the first flight.
Aircraft I've flown: A300/A310/A320/A321/A330/A340/B727/B732/B733/B734/B735/B738/B741/B742/B744/DC10/MD80/IL62/Bae146/AR