If you desire to discover the whole beauty of both Vietnam and Laos, I think 7 Days is too rushed. Therefore, you can consider spending 7 days in one of them: Vietnam or Laos. However, with 7 days in your hand, you can also have glimpse tour in both Vietnam and Laos.
You can consider some itinerary as below:
Option 1: Vietnam only
DAY 1: HANOI ARRIVAL
DAY 2: HANOI-HALONG
DAY 3: HA LONG-HANOI
DAY 4: HANOI CITY TOUR
DAY 5: HANOI-DA NANG-BA NA HILL
DAY 6: DA NANG – HOI AN
DAY 7: HOI AN DEPARTURE

Option 2: Combine Vietnam and Laos
DAY 1: UDORN – VIENTIANE -VANGVIANG.BAN CHIANG
DAY 2: VANGVIANG-LUANGPRABANG
DAY 3: LUANGPRABANG-XIENGKHOUANG
DAY 4: XIENGKHOUANG-SAM NEUA
DAY 5: SAM NEUA-HANOI
DAY 6: HANOI-HALONG
DAY 7: HALONG-HANOI-DEPARTURE.

Hope this information is useful for you.
Have a nice trip!