You're right except about the head to head battle. VC and NVA would go out of their way to avoid taking on the Americans in an open battle. Without exception, they were outgunned and over-matched and they were well aware of that. These simple facts of life left them with little alternative but to stage a guerrilla style war.
The Tet offensive took place before I got there but it was clearly an attempt to do what we had been doing to them all along. That was to give the impression that they could take any place at will. We would do that all the time by air assaulting onto a hilltop well within their AO and set up a fire base wherever and whenever we wanted to.
During Tet 1968, the VC and NVA didn't stand a chance of holding any of the cities they attacked. They sure as hell weren't even close to holding Saigon. Their concept was that the people of South Vietnam would join them against us. That went over like a lead balloon. They weren't even close to taking Saigon. 19 VC reached the American embassy grounds there but never even gained entry. But I remember the news media portraying it as virtual defeat of the Americans.
For background you should realize that through 1966 N. Vietnam suffered huge casualties and devastation of supplies through bombing in the north and fighting in the south. Just 10 days before Tet, the battle of Khe San took place. The same General (Giap) who had defeated the French at Diem Bien Phu (1957) also conceived Khe San. His purpose at Khe San (besides victory) was to distract the Americans from the cities of South Vietnam.
It was that very Tet offensive that inflicted such heavy casualties on the VC that they were not considered a viable fighting force after that.
The misreporting, along with Communist North Vietnamese agents in the United States, led to demonstrations in the streets by Americans in protest of the war. Gen. Giap later wrote in his book, that the news media reporting and the demonstrations in America surprised them. Instead of seeking a conditional surrender, they would now hold out because America's resolve was weakening and the possibility of victory could be theirs.
Here's another bit of info for you. Bui Tin (the guy who received the unconditional surrender of South Vietnam) had this to say when a Wall Street Journal reporter interviewed him. Tin said, "America lost because of its democracy; through dissent and protest it lost the ability to mobilize a will to win." Tin went on to say that Gen. Giap (Commanding General of the North Vietnam Army) had advised him the 1968 Tet Offensive had been a defeat.
So, to answer your question, no the VC's intent for Tet was victory and they got their collective butts handed to them. Their greatest weapon turned out to be the sensationalist American media not guerrilla warfare.
Sorry for the long winded post but I am not sure how much background information people who read this might have.