The US side sets up first. Put the VP marker at 60 and port capacity at 2. Thai port and additional airbases are not available until normally scheduled. One Thai airbase is usable on the first turn. All units 'At Start' plus those in the respective Available Boxes set up as per the instructions.
New units arrive as scheduled and all rules governing new units are in effect.
All other Political Events are available. Do use the Victory Points Schedule, though of course costs and awards for Political Events not allowed may not be taken or debited. This is hard for the US to achieve in the timeframe given. Even if the American does win this scenario, in real world terms this would not mean the US would win the war, long term. It does meant that probably 1968 would not have been the decisive year that it was.