It is simple:
remember what George Clinton said: "To each his reach, and if I don't cop it ain't mine to hold", Then: consider that you are thinking about #1: developing good soil, and with billions of soil-dwelling helpers. Work with them, not against them. How can you accelerate soil formation if you can't add Your contribution as an animal? If you can't pee on it it's TOO TALL. (I've been injured on a ladder more than once: Gravity is not just a good idea: IT'S THE LAW!) Curiously enough, soil building helpers like it dark and reasonably moist. I have posted on this subject before, but I am not fully caffeinated and have no hope of finding it, better I just give another version: instead of importing heavy soil, get down and dirty, and trench into the subsoil, deepening the profile, aerating, and put BIG WOOD down first: a great way to recruit allies like termites, and remember to have a wheelbarrow load of finished mature compost (don't bother sifting it) on hand to inoculate each major layer as you work upward. Do this in the footprint of the garden "bed to be" or in a tired ol' bed that needs a boost. Leave mature weeds with ripe seeds to mulch the mud in the chicken yard where they will perish without leaving descendants while they feed the chooks, if you're not not in a frikkin' city with humans who find chickens loud and obnoxious, not soothing and pleasant neighbors and allies. SO: build no higher than you can stack it all, watering during every Hooglecompost/raisedgarden bed-building event, and consciously make sure to have spots that have finished compost/topsoil all the way down to the soil line so you can have squash plants in season without any un-needed fallow season: the first crop will ensure you water well enough to accelerate the soil-forming process the more sensitive veggies need. It's a good idea to have inoculated legumes in all the early annual polycultures to accelerate the transformation of cellulose into more available carbon. SO: less time hauling heavy dirt around about, and getting yield asap while reaping other benefits like improving aeration, texture, nitrogen- well, you can add all the additions you can dream up, as you the designer becomes the recliner.