Three comments for you.

First, when I was in Hanoi a few years ago, I stayed at the Hilton Hanoi Opera, and it was a great, and very modern hotel, attached to the old Hanoi Opera House. It was very reasonably priced for a 4 star hotel. I think it was $108 per night, you can still get rooms there for less than $200 per night. It is also centrally located, and we walked to many places from there. We arranged with the hotel in advance for one of the hotel's car and a driver. The cost for that was less than $50 per day if I recall, and that included a generous tip. They were using the Mercedes E class then, but now they are using the BMW 530. The drivers all spoke English, and it was well worth the cost.

Second, while in Hanoi, you must go for a meal, or at least drinks at the Hanoi Press Club. The food is fantastic and the service is excellent.

Third, surprisingly, there are quite a lot of gay people who advertise themselves online. I am not sure about gay bars, because I did not visit any, but depending on the sites you go to, there are lots more guys than you would ever expect. For example, on a site that I frequent, SilverDaddies, there were 155 guys with profiles who live in Vietnam, and a lot of Vietnamese guys are particularly interested in older white men. It is kind of a "rice and potato" sort of thing.