Check out the CA pass holder black out dates, crowds will be lower then. Crowds tend to be manageable in the morning, but PACKED at night. A lot of locals stop by after work or just for the evening. Waits for the parades or the fireworks can be really intense because locals are just stopping by to grab a snack and hang out and chat for several hours while they wait for the show to start.
When we first started going to Disneyland after only having been to DW, it felt like Bizzarro DW. Everything is the same, but... not. The walkways are smaller, the ride vehicles and line spaces are smaller, there can be some pretty major backups because of the smaller walkways. Like, we avoid Adventure land just before Jungle Cruise all the way back to the Tarzan Treehouse if we can help it at all. It's a zoo there, and there have been some times when we were really stuck and could not get through. There are cut throughs.
You are going to be really impressed with most of the attractions and the shows. The Disneyland fireworks are amazing compared to Wishes. It's about 20+ mins long, so be aware of that if you are going to be holding kids. Try to get in the hub, because there are special effects that shoot off from all around the hub. But other places in the park are good, too. Try to watch from IASW at some point, too, because they project a little show on the facade.
Fantasmic is much better as well, but getting used to not having a stadium can be a bit of an adjustment. Walk all the way to the far side, and crowds will be much less. We usually sat in the area just below the dessert party (which doesn't seem worth the cost to me, personally, you get one small box of desserts and the same seat everyone else gets for free, but different strokes, and all that jazz). Anyway, I don't want to spoil the show, but it's really great at DL compared to DW.
The original attractions at Fantasyland are really cute as well. Alice is fun, be aware there are no fast passes for Peter Pan, and that line is always an hour long. Get there early.
We also LOVE DCA. We ended up spending most of our park time there. It's more laid back, the walkways are larger, there are fun things for the kids like the Bugs Land, and Redwood Creek. Holy cow, the kids would spend hours and hours playing there. It's crazy.
Also, IMO, the food at DL is much better as well. Even the counter service seems better. We like the gumbo place at New Orleans Square, and the Zocalo (sp?) mexican place as well. And, you can make ADR's for character meals the day that you want them. We were never told they didn't have anything available. We tried them all, and liked the Lilo and Stitch the most (now Mickey and Friends. Meh). Ariels has pretty awful food, but the interaction is great, and the patio is pretty.
Have fun!