One thing to bring up first: Ho Chi Minh was not the one wielding power in North Vietnam / Democratic Republic of Vietnam (DRV). Since 1963 he and other 'North first'-ers (those in the DRV regime that wanted to build socialism in North Vietnam before seeking to unify the country) been sidelined by a more militant hard-line faction led by Le Duan. Into the mid-1960s, Le Duan and his backers continued to sideline old party members, in particular those affiliated with or having trained in the Soviet Union. Purges removed many old hands from the 1940s-50s.
There was an attempt in 1966, called Marigold, initiated by Poland with the aim of ending the conflict between the US and DRV. But resolving the fundamental Vietnamese conflict between the DRV and Republic of Vietnam (South Vietnam) was not part of that initiative and was generally insolvable. Each regime in South and North Vietnam claimed sole authority over a unified Vietnamese state. So Marigold had the aim of ending just one aspect of the war, not the entire conflict -- that was not possible without one state dissolving itself. Nevertheless, on the issue of US involvement this Polish initiative still failed quickly.
The main issue was that each side was only willing to vaguely entertain negotiations, gaining some strategic advantage (say, for the DRV, a halt to bombing) but not willing to abandon their primary objectives: for the DRV under Le Duan it was unify Vietnam under a socialist regime; for the US, rebuffing the DRV sponsored insurgency in South Vietnam and maintaining a non-communist state in the south.
At this point neither side was willing to compromise on their objectives, and Le Duan would never waiver from his aims. He was a southerner who, during the First Indochina War (1945-1954) commanded DRV forces in the provinces now part of South Vietnam. Bringing the south under the DRV's control, 'liberating' Saigon, was a fundamental personal and ideological goal of his. Indeed, he came to power by harshly criticizing Ho Chi Minh's "error" in negotiating for peace in 1954 -- that was a blunder, he said, responsible for the division of the country. The only peace Le Duan would abide by was the one he got in 1973, which conceded a brief pause or 'decent interval', but ultimately allowed for the resumption of an aggressive military campaign against the South Vietnamese state and the unification of of the country under the Vietnamese Communist Party and Le Duan's sole leadership. It also meant defeating two other US allies, in Laos and Cambodia, and ensuring that their revolutionary communist leaderships were friendly, and at least not hostile, to Hanoi.
In the end what Marigold revealed in 1966, as one historian succinctly put it, "instead of [a] 'last chance,' Marigold confirmed no chance at peace at the juncture of the war."
James G. Hershberg, Marigold: The Lost Chance for Peace in Vietnam (Washington: Stanford University Press, 2012).
Lien-Hang Nguyen, Hanoi's War (Chapel Hill: University of North Carolina Press, 2012).
Pierre Asselin, Hanoi's Road to War to the Vietnam War (Berkeley: UC Press, 2013).
There were long standing negotiations and attempts to negotiate by the Americans throughout the war, although as the USA didn't recognise north Vietnam as a country, and as the south Vietnamese regime was wary of talking, much of the negotiations had to take place in secret, and they took many years due to mutual mistrust and the changing situation in the war. Eventually an agreement was reached though (the Southern regime fell several years after the withdrawal after the US congress drastically cut its aid to the regime)
Probably the best place to start is getting a biography of Kissinger as he was the key US figure for most of the negotiations (his involvement began before he went to the White House). I'd recommend Niall Ferguson's biography since it's the most up to date and complete so far, although only the first volume is currently out which only takes you part way through the negotiations.