We have two kids DD11 and DD2 we will only be there for one day which park should we pick...in your opinion
When do you think you'll be going to Disney? Time of year can sway an opinion on how to tour the parks.
I agree, with the parks so close together, purchase Hopper Tickets. That is if you have the time to hop.
Check the hours for both parks. Know when they open and close.
During a season where the parks open early and close late......
If the parks don't open at the same time, begin your day in the one opening first.
End your day in the park closing last.
This is how I'd spend the day. Even if it meant hopping more than once.
During a season where the parks do not open until 9am or 10am and close at 7pm or 8pm.
My touring strategy would be different.
If it was our very first trip, I choose
Disneyland for the entire day.
If the family had been to the parks before then I ask DD11 to help decide the touring plan.
Knowing the general travel date would be helpful.
Good luck
Geemo