I have booked my room at Candy Cane for Sunday, Dec. 10 to Saturday, Dec. 16. I plan to fly in late Sunday afternoon and take an early flight out on Saturday. Whether I fly into Orange County or Long Beach will depend on the prices and how many points I still have available at Southwest after flying to WDW in October. Last September it only cost me $220 round trip to Long Beach.
Now for answers to your questions and useful information.
John Wayne / Orange County is a small (three terminal buildings), modern airport that doesn't seem too busy.
Long Beach Airport is smaller (two terminal buildings) and is makng renovations to convert it from a 1940s airfield to a 2020s transportation destination.
At Orange County, American uses terminal A and Southwest uses terminal C. Shuttle pick up is outside of terminal A, so SWA passengers have to make a short walk north. Shuttles drop you off at the appropriate terminal.
The last time I flew to Orange County and stayed at the Candy Cane, I arrived on a Tuesday at 10:55 am, left on the shuttle at 11:30, made one stop to drop off another group and arrived at Candy Cane at 11:50 am. (And they had a room available for me!) The following Saturday, the shuttle picked me up at 4:15 am for my 7 am flight. We got to the airport at 4:35, but there was nobody at the Southwest counters until 5:15 am.
Last September when I flew into Long Beach, I used a private shuttle since there were no shared shuttles available. (Next time I may use a taxi; they have flat rates to/from Disneyland.) My experience was similar, except the trip took twice as long due to the distance from LGB to Disneyland. The day I flew home, the shuttle picked me up at 5:15 am for a 7:20 flight. Southwest was open when I arrived and I had checked my bags, gone through security and walked to the gate by shortly after 6 am.
It is a half mile from the Candy Cane lobby to the security check outside the park entrances. Downtown Disney is another quarter mile past security.
If you need to buy anything, the corner of Harbor and Katella has a 7-Eleven, CVS and Walgreens on the corners along with several restaurants. There is a shopping mall a half mile east on Katella.
There is an Alamo car rental location on Katella Ave, literally right around the corner from Candy Cane. I used it in 2017 to spend a Sunday at Universal Hollywood. At that time a one-day car rental was $30. It took about an hour each way to get to Universal. The Neon Museum is in Glendale, just east of Universal, so plan on the same amount of time (or more, if it's a weekday) to get there and back. There are other car rental locations within a short walk. Bear in mind that renting a car at the airport (or returning one rented elsewhere) may cost more.
At the DIsneyland Resort, purchases may be made with any form of payment that DIsney accepts: Cash, credit card, DIsney gift card, etc. Mobile ordering is available on the DIsneyland app for most quick and counter service locations. The web site says you can also use your "mobile wallet" to pay for food and merchandise which I assume means either entering a credit card in the Disneyand app or using some other compatible app like Apple Pay. In other words, it's just like Disney World but without Magic Bands.
It looks like Disneyland now supports MagicBand+ and looking at the questions
like this one on PlanDIsney it looks like you can link tickets and credit cards to them. The down side is you have to pay $40 to buy an MB+.
Park hours for Dec. 12-16, 2022 (the same week we're going in 2023) were Disneyland 8 am - midnight, DCA 8 am - 10 pm.
Any more questions?