Walkers can arrive the earliest at MK, EP (IG entrance), HS. No one can really walk to AK.
It sounds like it’s often a toss-up between buses/rideshares/your own car at AK, HS, EP (main entrance) for which vehicle gets there first. Those three hold cars at the parking entrance until about 1 hr before park opening. Show up much ahead of that (15 min?) and they just tell you to keep driving around.
At MK, buses go directly to the MK parking lot, while cars go to the TTC, where you then have to take time to take monorail or ferry to MK. I think rideshares also drop off at TTC if you say you want to go to MK. MK tollbooths are like the other 3, opening about an hour early, otherwise drivers circle around until then.
Here’s the tricky part:
If you want to be a walker at MK/EP/HS, then you need to be dropped off/drive yourself and park at a nearby hotel. Most hotels won’t let you do that without an ADR, or maybe a mobile order but some places like CR are really strict on not even a mobile order. BUT: Swan/Dolphin let you get dropped off there, or park (daily charge but you can dine there and get it validated). You can also use rideshare and get dropped off at the Speedway gas station to walk to HS/EP (mostly for HS). If you’re going to EP (opens later than HS) you can also bus to HS then walk/boat/skyliner to EP to be like an early walker.
It all comes down to how early do you really really want to be there - one of the first few in line (walk)? Or some of the first cars/first buses and you still get there plenty early to do rides before opening? And at what cost/hardship - $$ rideshare/ADR or longer walks? Also bus vs your car - you can have masks off in your car and no waiting for bus to arrive, also do you want to drive/navigate or not, do you have small kids needing car seats?
So many factors. It’s a lot of personal preference. Yes, it’s clear as mud.