For the first few years, I was with friends, staying in a hotel in LA and we did one day trips to
Disneyland. I agree, when you have never been and really want to go, and all you can do is a one day, open to close, then yes it is worth it.
Many posters here on Disboards have grown up being able to go to the parks, and will say that you need more than 1 day and you need to stay local. But that just is not possible for everyone.
I posted this in another thread, some things to consider as a first timer
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 your eyes, all the different sounds, even the scents and smells, will catch your attention.
I was woefully wrongly dressed for my first visit. I had no idea about the miles and miles of walking. Make sure to wear comfortable shoes and clothes and really downsize your handbags / park bags. First timers think they need so much stuff but hauling a heavy bag with stuff thats never used / needed will wear you 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 your discomfort as the goes by.
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 know about the rides and themes before you go, look at the differences between rides like Haunted Mansion and 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. Have a look at Disneyland website, all the restaurants and food options are there, with all the menus, so you can budget and pick food options which are best for you, not just the ones everyone talks about online.
I found on my visit 2 weeks ago, 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.
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. Talk to your family, maybe just being in Disneyland Main Park is enough for a first 1 day visit. I found park hopping on a one day put too much pressure to do and see it all.
When you do open to close, having some chill time / down time in the afternoon is important. Your mind wants to keep going but your feel and body just wont, so recharging, ready for the second part of the day is important.
I usually 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.
Talk 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. With just one day, you need to figure out before hand whether you want to stop and do the new character interactions or just take a photo in passing and keep going to the next thing.
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.