When you are staying in Carlsbad, you can eat at a Ruby's on the end of the Oceanside Pier in Oceanside.
I haven't been to Legoland in a few years. I suggest eating the apple fries while there. The aquarium is a let down, but since you'll be there for 3 nights, you'll probably want to go there. It doesn't take much time. I never went to the water park as my kids were already too old when they added that.
If you do like aquariums, the Birch aquarium is excellent.
https://aquarium.ucsd.edu/
You could make it a full day in La Jolla by also visiting the wild seals and sea lions at the Cove and Children's Pool a few miles down from the aquarium.
The Zoo could take a full day. Balboa Park (which shares the same property) has lots of museums and is very popular. The Science museum is hands on and has a cool IMAX movie theater inside that shows docmentaries.
https://www.rhfleet.org/
Ramona is a big drive from anything other than the Safari Park and there isn't anything to do in Ramona. I guess you'll be close to Julian, which is our mountain town that everyone goes to for apple pie. Julian is pretty dead during the week and very busy on the weekends.
I've lived in San Diego for almost 50 years and I can think of lots of things to do, but I keep getting thrown by the driving from Ramona. It will be an hour drive to anything I can think of and I hate being the car - so, that's making it hard for me to post a lot of stuff. Do you have any particular interests?
Saturday and Sunday there's an open house for a senior dog rescue in Ramona called Frosted Faces. The hours are very limited, but it is nice to see the compassion and the dedication that so many volunteers are willing to put in to save the former pets who have landed in various shelters because they are "old" or have health problems.