What is included with a park hopper ticket to Disneyland California?

Answer 1

Admission to Disneyland and/or California Adventure, and the ability go between one park and the other one as often as you like during the day assuming the park you want into has not reached capacity ... more likely to happen to Disneyland than California Adventure; if the park isn't admitting guests for capacity reasons, they're not admitting guests, whether they have regular tickets or Park Hopper tickets.*

You don't need a Park Hopper to leave a park to, say, go back to your hotel for a bit and then later re-enter the same park, you just need to get your hand stamped when you leave.*

Also, if you have multi-day passes without the Park Hopper option, you don't have to use them for the same park the whole trip, you just need to pick one or the other each morning and stick with that park for the rest of the day.

The Park Hopper add-on is on the pricey side for what it does; most people may be better off just planning on staying in one park for the whole day. That said, the Park Hopper may make sense to you if

1. You're only going one day and there's at least one thing in each park that you absolutely must do... though a two-day pass that would allow you to spend one full day at each of the two parks is only $26 more than a single-day Park Hopper pass on a peak day.
2. You're going three or more days; the additional cost of the Park Hopper goes down not only on a per-day basis but also in absolute dollars on multi-day tickets. $6 extra per day ($30 total) for the Park Hopper option on a 5-day pass is a lot easier to swallow than $50-60 extra for the Park Hopper option on a single day pass.

(Any time there are prices above they're accurate as of August 2016, but you should check the Disney web site for current pricing to see if there's been a change.)

* The Cast Member manning the exit gate will generally know if the other park is closed for capacity issues. Even if they haven't specifically been told by their management, the parks are literally like 100 yards apart; any gate employee who's been there long knows what normal busyness in the Esplanade looks like versus what "the other park is turning people away" looks like. Before leaving the park, you should check with them. It's a good idea to ask them if they're expecting capacity crowds later in the day at the park you're leaving as well, because it may impact your decision to leave if you're not sure you'll be able to get back in later (Disney usually has a pretty good idea about things that might cause this to happen and warns Cast Members ahead of time).