The options were to attack North Vietnam and its sanctuaries in Cambodia far more aggressively and sooner than eventually happened, and also to not negotiate with North Vietnam, since Hanoi repeatedly faced collapse in the war until the US let off the military pressure in hopes of kick-starting peace talks, which North Vietnam saw as weakness by the US. The advantages were manifest - defeat the enemy. The disadvantages were feared to be Red Chinese involvement, except Red China was more frightened of escalation than the US was; it was not until it saw that the US would not press to win that Red China was emboldened enough to station troops in North Vietnam and increase military aid. I hope that this is the answer that you were looking for and it has helped you.