the "best way" for this because of the number of dead knots would've been a drum sander, I think - at least that's my opinion. I wanted to bull through it faster, but you can make a mess of breaking the knots and then they come out or are uneven on the surface with broken bits sticking out. I'm sure that I sized them some before this with a try plane or a giant cocobolo rough smoother that I have that's magic on this kind of work, but the knots were the hang up in this case.
As jacob said above, you could just break them out all over the place, go back and fill them (it would take about the same time) or you could spend about 10-15 minutes on each like this and then chamfer the corners and fill just whatever breaks out on the corners (some do).
It seems like unnecessarily thin shavings, but it's what the wood would allow. If it was bright and clear wood with straight grain, it would've allowed a lot more - I'll always go as fast and heavy as the wood will allow and started faster, but it made a mess of the dead knots combined with very soft grain behind them and this ended up being faster and just as pleasant.
Better wood would've been the best case, but there was a chance that this bed would get pitched. Daughter wanted a loft bed, but she's a sleep walker. She's managed it so far now for almost a year, but if she hadn't, it would've been thrown out. using cherry and a clear finish was ruled out by both the princess and the queen (that would've been my first choice). The sleep walk thing is also the reason for the cattle pen style top rail.
Comparing planing here, this wood is worse than something like curly maple -I don't plane much junk wood, so I wouldn't have known. Keeping the dead knots from breaking out into a spiky dirty mess is trouble. I posted this picture a few months ago of an 1840s or so English plane that I came across, setting the plane up and planing with the same kind of setup (thicker shaving) in curly maple.
View attachment 109104
Luckily, it's all a variation on the same theme - you go as fast as the wood will allow and the prep of the plane and then setup for use is kind of the same across the board. Whatever the wood allows, you go as fast and heavy as you can without battering elbows and shoulders, and then it's just work in rhythm.
There is a reason that most of this was done with a 4, though - pine is friction/sticky and once basic straightness was established, a bigger plane would've been more work and wasn't needed. This needs to be eyeball straight.
What I was really going for was a result where you couldn't easily tell that the posts were laminated (can't) or that the wood was really cheap (can't tell that either). The load bearing parts that are lateral are all yellow pine, which planed a whole lot more easily because all of the knots were live.
Despite jacob's uneducated comments above about what's easy planing and what's not, reality when you put nuts to the floor with hand tools is that some of the most spectacular lovely looking stuff isn't that difficult to plane cleanly, and it's the junk that makes a challenge.
And industrially, that junk, if used, would be done through an industrial drum sander. There's a guy about 45 minutes from me that I used before I learned to plane - he's got a beach 52 sander. It's magical. It's also three phase and would never fit in a normal house - three drums, all three oscillate and the last drum is something like 80 or 120 grit paper. It'll take 1/8th inch off of a 20" wide maple panel without much complaint and leave a sanded surface that just need a little bit of finer sanding. A half hour of time on anything you can haul will more or less get a sanded surface for an entire project like this for about 40 bucks.
But on the plane setup and set - no part of it is difficult, it's just getting a small amount of experience to do it a couple of times right and then it just becomes routine because you know what to feel and what to look for.