Closest major city is Nha Trang. It's smack bang in the middle of Vietnam, you can get to Nha Trang from Saigon/HCMC either by flight or overnight train. It's then about a 90 minute drive North from Nha Trang to where we stayed.
Probably about 60 minutes North there is a reasonable size town that has hotels etc. Where we were staying there was basically no acommodation. We grabbed a spare room at a cousins house.