[Gurachn]

Yeah, the book is worth a look if you are interested in the period.
Well researched, but with the same focus on the characters that he gave to Blackhawk down, both from the US/ARVN and the NVA/VC/NLF side.

Interesting mix of weapons too - Flame tanks, 106RR on a mule, the cool and surprisingly effective Ontos (6 106RR rifles!)... heavy use of CS gas (can that be handled?)
Monty's Map does a good job of capturing the layout of the land, though it does have a bit more rural look than the actual city.
Especially around the citadel, I wonder if there is a way to get the look of the massive stone walls, fortifications and ornate buildings of the citadel?

Bit of a challenge here, but this nasty 'knife fight in a phone booth' was pretty much the tipping point for the US in Vietnam.