Is it possible to do kristinsund to alesundby car in a day,and road is open in may
Road is open the whole year, 24/7.
The route includes a ferry ride from Molde to Vestnes. The drive it self (incl. ferry) takes 3-4 hours depending on waiting time for ferry (departs every 30 minutes on weekdays).
Doing the Atlantic Road (Atlanterhavsveien) will add 20-30 minutes pure driving time, but most likely more as you'd want to stop to take in the scenery and feel the wind off the Atlantic Ocean blowing onto your face.