Just got back from two days at Disneyland/California Adventure with my 10- and 8-year-old kids. First trip to Disney anything since I was a little kid. Usually I'm a big planning guy for trips, but this kind of came up last minute, and TBH the Disney planning cottage industry is pretty overwhelming. I read through the last couple of pages on this thread for tips and it helped a lot, special thanks to @mdmost in particular. He also linked a website a couple pages back that we used a lot.
Here's a long list of thoughts from a first-time (as an adult) visitor:
For kids around mine's ages, I would say the ideal would be 2 days in Disneyland and 1 day in CA. We had 1 and 1. We got to pretty much all the big stuff in DLR, but there was a ton of smaller stuff we didn't get to, and we didn't get to re-ride some bigger stuff we wanted to. We covered pretty much all of CA, although to be fair, the water ride and Guardians of the Galaxy, which are two of the bigger rides, were closed the day we were there.
First off, you already know this, but Disney knows how to get in your pockets. Big time. The trade-off is that pretty much everything is first class. For the most part, they're giving you good value for your money. I don't think you can go into it looking to penny pinch. It costs what it costs and you gotta just chalk up all that money to greasing the wheels of your fun vacation.
To be more specific, I think the Lightning Lane stuff is worth the money. The general strategy, as espoused by mdmost and the website he posted, seems to be to run to the most popular ride (Space Mountain in DLR, Radiator Springs in CA) as soon as you can and knock it out while simultaneously getting your Lightning Lane working. From there you can just keep working the LL and fill in with shorter lines. If you do it right, you'll pretty much just be going from ride-to-ride for as long as you want.
Even if you don't do the LL, the app is essential. It shows all the current wait times for all the rides, you can order food, etc, etc. We were on it all day. I had to bring an external phone charger battery pack.
To that point, Disney is very good at keeping the lines moving. They aren't fucking around. 60 minutes of a moving line is way better than 60 minutes standing still. And of course the queues typically have excellent theming and shade.
Overall, we preferred Disneyland to CA. My 10-year-old said DLR felt "magical" in a way that CA doesn't. DLR has a fun, 1950's, old-school feel to it. In contrast, CA just feels like another amusement park. Granted, it's a very well done one because it's Disney.
My personal opinion is that CA needs a few more rides. Like I said, we knocked it out in a day, no sweat, although Guardians and the water ride were closed. Some of the theming is super well done (Cars and San Fransokyo), but they have to fill all those buildings up with something, and it's just more gift shops and food places. I found myself thinking "instead of a park with 30 gift shops, how about a park with 20 gift shops and a couple more rides?"
That said, Incredicoaster is great. One of the better roller coasters I've ridden. Just the right amount of intensity for young kids. The two shooting gallery rides were pretty cool (Web Slingers and the Toy Story one). Radiator Springs is fun, and was obviously the most popular ride, but I felt like the "roller coaster" portion of it was too short.
Avengers Land feels like an afterthought compared to the rest of CA. Not much to do over there. I'm not big into that stuff anyway.
Don't sleep on the forest playground thing in CA. It's very peaceful over there. Great spot for mom and dad to chill while the kids run around on their own. My kids could have stayed there all day.
As for Disneyland, it has all the classics that you remember as a kid. Space Mountain, Matterhorn, Big Thunder Mountain, the submarines, the cars that kids can drive, Pirates, and on and on. It feels very nostalgic if you've been there is a kid, but on the flip side it's all well maintained, not shabby, and good to go. Very, very different vibe from a modern amusement park.
As for newer stuff, the Indiana Jones thing is cool and unique. It definitely throws you around quite a bit. Rise of the Resistance is probably the coolest and most unique amusement park ride I've ever been on. They did a great job with that. My wife and I both agreed that it was the highlight of both parks for us.
Star Tours (the old school motion simulator that's been there for years) made both me and my wife motion sick as hell. The kids loved it of course. After that, we didn't attempt the Millenium Falcon ride, which I understand is also some sort of motion simulator.
I got fucking drenched on Tiana's Bayou (front seat). So much so that I had to run back to the hotel and change clothes so I didn't freeze my ass off after sunset.
Overall, the food in both parks is very meh. I don't remember anything memorable. Maybe a dessert or treat somewhere. We found the food outside at Downtown Disney to be a little better, but nothing special.
I'll post some general Southern California-related thoughts in the LA thread.