Pretty much straight north of Saigon and then towards the NW. Phuoc Long and Binh Long on some maps show pretty close to where I think the LZ was. Actually though, we never really had all that good an idea of where we were in relation to the big places. We'd get small quadrangle maps and orders to go to a certain coordinate, so we'd read hilltops, streams, & etc. to navigate and end up where we were supposed to be.
I was never in Chu Lai area that I know of. I think that's farther north of Saigon and closer to the coast.