Morning slot
Arrive at dawn for the square queue; papers and dress ready (cover shoulders and knees — shorts/tank tops may be refused). Tickets and open status follow the site/official notice; entry is often free but security is strict and closed days happen. After the exterior, continue inside — do not burn the morning on plaza selfies.
Same-day continues
Same day: stilt house, One Pillar, Flag Tower or Thang Long Citadel — all inside Ba Dinh walking range. West Lake, Literature temple and Beer Street are other days. No night lanes after a mausoleum day; one hotel-area meal and stop so tomorrow keeps West Lake or south.