I'm kind of a fan of public transportation. It's always an adventure in LA and OC. There's a way to take buses from Disneyland to LAX which is cheap, but again - it would be an adventure. I might try it, but then it would depend on your friend's tolerance for occasional aberrant behavior and a good deal of patience. I believe it's possible to get there exclusively on LA Metro starting at the route 460 stop on Harbor and then transfer to the Green Line in Norwalk and then to the LAX/Aviation station before taking the free airport shuttle that hits all terminals. I think the cost would be less than $5 including the TAP fare card which costs $2.
https://www.google.com/maps/dir/Dis...7636c3969!2m2!1d-118.4083509!2d33.9439667!3e3
But for getting from Disneyland to the Knott's Berry Farm Hotel - that's easy. Anaheim Regional (formerly Resort) Transportation will do on-demand rides between designated points where they have stops. I've used their stop in front of the Knott's Berry Farm employment center and really close to the Knott's Berry Farm Hotel, even though I wasn't visiting Knott's Berry Farm. Once I was staying at one of the seedy motels about two blocks away. It was the closest designated stop to where I needed to be; the next closest was near Medieval Times.
It's a little tricky at first, but the A-Way-WeGo app has a way to purchase passes and to request on-demand rides. Some of the routes are fixed (mostly hotel routes), but those are surrounding Disneyland. But if you have some random route between points that they service, you can make up your own bus ride. They'll try to combine as many people into the same trip as possible, but that's not a given. I remember trying to get from my hotel on Harbor to the Honda Center to walk an NHL game, and there were a bunch of people going the same game. I believe it's $4 (no child discount although I think below a certain age children are free) one way and $6 for a day pass. They might go as far south as the Shops at Orange, west to Knott's Berry Farm, and east to the Anaheim train station and near Angels Stadium and the Honda Center. There might be other places I've missed, but I haven't researched all the places they go. An older map of what used to be their fixed routes might give an idea. However, many of the routes they show don't exist any more
https://apps.apple.com/us/app/a-way-wego/id1589114302
https://play.google.com/store/apps/details?id=org.rideart.awaywego&hl=en_US&gl=US
Their website is hot garbage though.
https://rideart.org
The places they serve are mostly tourist spots or near major hotels. In Buena Park the only stops I've figured they go to are at Knott's Berry Farm, Medieval Times on Beach, and the Fairfield Inn on Orangethorpe. But to give you an idea of how random it can be, the first two rides I took (with my kid) were from the train station in Anaheim (we came in on Amtrak) to Medieval Times and then from Knott's Berry Farm to the Anaheim Packing House. These were not common routes, but it was great how I could get between random points of my choosing.
I have felt kind of guilty being the only passenger several times. Other times it was just the kiddo and me. It is so bizarre being the only person on a trip from Harbor all the way to Medieval Times - maybe about 8 miles on a 40 passenger diesel bus (most of the fleet is electric now). I made that trip last New Year's Day only to find that Porto's wasn't open on New Year's Day. I mentioned to the driver that I felt bad being a solo passenger, but he said that's part of their service to make it convenient, and otherwise they'd have nothing to do during certain parts of the day. But it was a nice walk to Knott's where I had a bunch of time (checked out Build A Bear and other stuff in front) before my next on-demand bus ride was scheduled back to my hotel.
and I don’t want to drag the car seats to Knotts obviously. 
