Seems the a6000 has a relatively short battery life (250 shots per charge). Did anyone try to optimize usage and what was done to achieve it? How many shots did you manage to get?
What happens if the prefocus AF is switched off?
Would operating the a6000 only using the EVF help?
Can WiFi be de-activated or switched off?
Anything else to conserve battery life?
700 shots, with any battery, is feasible.
The biggest battery drain (by far) is the LCD/EVF (EVF being worse).
Turn off the auto-review (no chimping) and set the time-out to be less than 1 minute.
Make sure the EVF does not trigger the camera to go back on when dangling against your chest.
Then, the number of shots merely depends on how long it takes you to compose each shot. You can count on roughly two hours of 'display time', and can derate from there. AF, shutter, even processing (RAW/JPG) have little impact. To get 600 shots in 180 minutes, you should take no more time than 90/600 = 18 seconds per shot, on average.
AF and WiFi do not impact this as much as most fear. WiFi on a cell phone drains batteries faster
But, consider the time you may take to look at images, chimping or not, it is easy to see that you may spend 20 or 30 minutes just looking at images, or in preparation for shots.
As you get more comfortable with the camera, your number of shots will go up.
Again, auto-review set to OFF and time-out to be short are the biggest savers.
Airplane mode does not have a big impact.