July 2017 trip - crowds?

[AirDisney]

We have done WDW trips the past 4 years and we are considering a DL trip next year. Looking to go around the times for the D23 Expo (July 14-16). Just wondering about crowd levels out there during the summer and whether or not D23 significantly adds to the crowd levels at the park? Any suggestions as to whether it would be better to go to the parks during the week before D23 or the week after D23?

Thank you everyone!