How much time did straw hat pirate need to travel to the next island?
No, usually it takes them few days to reach that destination, why that is not shown is because nothing interesting is happening. We usually are only shown the stuff that is happening or when there is some important crew interaction ongoing.

One of the earliest examples i can think of is when Luffy has recruited Ussop and they meet the two bounty hunters(Joni&amp;Yosaku). They are talking about a chef and they tell Luffy that he can find one on a sea restaurant, but it will take them 2-3 days to reach it from the place where they currently are (the chapter in question is 42, page ~19).
Another example is the travel time between Dressrosa and Zou. 

Most islands require some time to pass, but since nothing interesting is happening there, Oda just skips those days.

Here is another relevant question:
How much time have the Straw Hats spent with each other?

Some general one piece timeline(although you did not ask for this, but it cannot hurt):
http://onepiece.wikia.com/wiki/World_Timeline