Yeah, that looks like exactly what I would have been getting into if I didn't make the sled. I cut that tree down last spring, and then work got shitty and I couldn't get to it until the fall. And I sat all winter with a bar mounted mill in the shed wondering how in the fuck I was going to get those 500lb logs up to a height where I didn't need to be kneeling or bent over them. Both options are absolutely unsustainable for me for very long. Shit, even just BEING on my roof these days fucks up both my knees and my back for a week from having to stand on that angle. There was literally no way I was gonna be able to do that.
I will say however, if you are planning on milling a ton of lumber, Izzy Swan's design is absolutely worth the couple days it takes to put it together. He's got a whole series on youtube of the upgrades he made too - he's got a winch to roll the logs up onto his mill, a boat winch to pull the saw thru the cut, and some other QOL stuff he's added to it to give you some ideas. My mill is coming apart when I'm done, so I don't really think I need to spend a bunch of time doing more upgrades to it, but you might.
Now, after 2 weeks, i'm finally heading out to the garage to my saw put back together. Just one goddamned thing after another. Get the cylinder head and piston, and then I need to torque the screws down, and I figure I should actually probably do it right and not guess on the torque. So, had to go buy a torque wrench, which I've been putting off for many years. And then I realized I can't actually attach said torque wrench to the screwdriver needed to mount the cylinder to the frame. And then I realized it's a T27 Torx bit, which almost nowhere sells, and then I realized that any extension I buy won't fit thru the holes in the cylinder. So yesterday was going all over town looking for a frigging 6 inch T27 bit and I ended up getting it overnighted from Amazon. $8 bit, $10 in shipping. FML.