I remember back to my first visit to
Disneyland in 2010. I went with California friends who had grown up going to the parks. It was really amazing to be with people who knew the parks, but after that first visit, all I wanted was to do the parks my way.
Some things to consider
Everything will be sensory overload, so just take your time and don't try to go from ride to ride. So many things will catch their eyes, all the different sounds, even the scents and smells, that you may not notice will catch their attention.
I was woefully wrongly dressed for my first visit. I had no idea about the miles and miles of walking. Tell them to wear comfortable shoes and clothes and really downsize their handbags / park bags. First timers think they need so much stuff but hauling a heavy bag with stuff thats never used / needed will wear them out faster. Also a backpack is easier than an over the shoulder / cross body bag. The strap on cross body bag can irritate the neck on someone who is not used to walking big distances in heat. And bring a cloth bag for merchandise shopping, again for a first timer not used to all the walking in the heat, plastic merchandise bags are hard to manage and bang off legs and will add to the discomfort.
I wouldnt even try to book restaurants or have a plan for the day. On my first visit after every ride, my friends would ask, what did I want to do next, I had no idea, so we just ended up doing the rides they usually do. My friends didnt understand that I knew nothing about the rides and attractions, they just assumed that I knew the parks like they did. I only knew about things like the Castle and Fantasyland and Main Street as thats all thats usually show on TV about Disney parks. Take the time to explain about the rides and themes, explain the difference between an omimover like Haunted Mansion and the dark rides in Fantasyland and the coaster like rides like Indiana Jones and Big Thunder Mountain and the simulator rides like Star Tours. My friends wanted to hit all the their favourite rides, where as I just wanted to explore.
The same with food. They always had lunch in The Plaza, so thats where we ate. It wasn't until I started going solo that I discovered all the other restaurants and food options.
Involve them with food choices, don't just assume that the food you eat or how you eat will be what they want. I found on my visit last week, that snacking throughout the day, was really fun, and gave me more flexibility in the park than planning sit down table service. When I first visited with my California friends their food budget was low, as they visit multiple times in a year so we ate at the cheaper places. Whereas with me, I visit once a year and have a higher food budget.
The same with shopping. My California friends didnt give much time to browsing the shops throughout the park during the day, as it took up time that could be spent on rides. Whereas with me, especially in the first few years when I wasnt sure if I would return the next year, spending time in the shops throughout the day is just as important as rides.
The same with nighttime shows. We staked out a spot right in front of The Castle for the fireworks, as thats what friends grew up doing with their families. When I started going solo I skipped the fireworks and went on rides and discovered Fantasmic and World of Color.
I would also do Disneyland Main Park, then DCA then Disneyland Main Park. I agree that a full day in each park instead of park hopper is a good idea. My first visit with my California friends was park hopper, as thats what they always did, but I would have preferred a slower pace in one park.
Also ask them about early mornings, late nights, chill out time in the middle of the day. When I would go with my friends we never got there for park opening, didnt have any down time in the afternoon and stayed until closing.
Now that I go on my own, I'm in the park for rope drop / park opening, take a break from rides between 2pm and 5pm and find a chill out spot to sit and people watch and then stay until close.
Ask your friends about characters. Meeting characters is not high priority for me, as I didn't grow up going to the parks and dont have nostalgia or an emotional connection but my California friends did and meeting characters was a must do for them.
Finally photopass. It wasnt until Covid and I spent time looking through my photos of previous visits that I realised I had no photos of me in the parks. I used Photopass for the first time on my recent visit and having good photos of me in the parks is something I love and will do again on my next visit.
The main thing is to be aware that this visit is all about them. They have no expectations, everything is a new experience, they wont want to know that Fastpass used to be free but now you have to pay for Lightning Lanes, they don't care that 3 day tickets used to get early opening access, they wont care that you can't hug characters anymore, none of that is relevant as its not part of their park experiences. What they see and experience on their first day is their base point.