Tips for public transportation in the DLR area:
If you're taking the ART bus, you'll need to purchase a pass ahead of time. You can buy a pass ahead of time on their website (they'll send it to your hotel so you can pick it up upon check in), from the kiosk near the bus bay in front of the Park's main enterance, and from many of the hotels in the area. Technically, most of the ART buses accept cash...however...in my experience...the cash fare box is not working on many of the buses. Not a nice thing to find out when one has been waiting half an hour for a bus after an open-to-close day in the Park...trust me, I know! Also...it's cheaper to buy ART bus passes for multiple days, rather than buying one per person each day that you use the bus.
You'll need the exact cash fare for OCTA buses and L.A. city buses; fare prices can be looked up in advance on the link I gave you.
On OCTA and L.A. city buses, make sure that you ask the driver "does this bus go to..."name of your destination goes here"", because some buses on the same routes don't take the entire route each time. Also because it's kind of easy to get turned around & lost when one is unfamiliar with the area.
The ART bus, the OCTA buses, and the L.A. city buses all have the standard bell/pulley to let the driver know where to stop.
Alot of the bus stops, no matter which bus line you take, aren't marked all that well (ie: they have a small sign, but no bus bench or bus shelter). I imagine though that if you're just using the bus to go to major attractions in the area & your hotel, you won't have any problem knowing where you are!
If you'll be taking the Metrolink trains, you'll need to arrive to the station in plenty of time to purchase tickets. As the stations nearby the Park aren't the "end of the line", the train only stops for a couple of minutes to allow riders on and off. Make sure to ask someone (a conductor, a police officer, another rider who looks like they know what they're doing

) if you're getting on the correct train before boarding. Both the Metrolink and Amtrak trains run on the same rails, so it can be kind of confusing even when one has been on the Metrolink many a time. So, it's best to ask someone even if you're pretty sure that it's the correct train
The bus route between Anaheim and L.A. is the 460; that bus picks up and drops off next to the taxi area in front of the main entrance to the Park. This is the bus to take if you want to go to Knott's (it's about a 10 to 15 minute trip).
That's all I can think of at the moment...if I remember something else, I'll post it...