It is so great to hear that you and your wife intend to visit Ba Be Lake in Apr 2016.
To visit Babe Lake, 3 days/2 nights is enough.
Please find our suggest itinerary as follow:
 
Day 1: Hanoi – Ba Be Lake (L/D)
With an early departure from Hanoi this morning you drive head north towards Ba Be Lake. This drive of 270 km, which will take approximately seven hours, takes us through the flatlands of the Red River Delta and up into the mountain areas north of Hanoi. As we progress north, the scenery becomes more and more picturesque. From our scheduled lunch stop it is only around two and a half-hours to our destination. Arriving in Ba Be town by mid afternoon we check in the host family Tay and then stroll around the village or a bit of exploration before sunset. You spend the night in the traditional house on stilts of Tay ethnic people.
 
Day 2: Full day in Ba Be Lake (B/L/D)
After breakfast at the host family you board on our private boat for a cruise on the Ba Be Lake. We can have a swim in crystal clear waters before having lunch in the local restaurant near the Water Fall Dau Dang. Following lunch we have the opportunity to work off our feast with a trek to Tay ethnic minority villages. A visit to this small hamlet will enable us to witness how little the lives of the people in these remote areas have changed. Cruise further to Puong Cave and head back to Pac Ngoi village for overnight.
 
Day 3: Ba Be Lake – Hanoi (B)
After breakfast you bid farewell to our host and drive back to Hanoi capital.