The open bus ticket that I purchased in Hanoi all the way down to HCMC allowed for a brief stop in Hoi An and Nha Trang. Hoi An as a stopover is preferable over Hue, especially if the DMZ is not of interest. The town is full of French architecture and a laid back atmosphere. Most memorable part of my 6 hours in Hoi An: A wooden boat ride along the Thu Bon River with the cutest kids suckering me into purchasing postcards.
Between Hue and Hoi An there was a brief 30 minute stop at Marble Mountain. I could care less about the mountain but I found out I could have a 1×1 meter marble statue of myself carved for $1,000 USD.
Regrettably I didn?t spend a long time in Nha Trang where the beaches are world class. Sandy white beaches with calm tropical waters speak for themselves.