I was always under the assumption that clear water was good, however, I’m sure you already know that blackwater is pretty discolored BUT nutrient-rich. The biggest challenge I can think of will be obtaining soft water in Georgia. Wells are prohibited in my area and using chemicals to obtain the correct levels just sounds like a nightmare. I have heard though that collecting rainwater is an easy alternative. I do not have the link but I was watching a youtube video of a guy who had a rainwater 55g setup with no filter I believe, who bred neon tetras like crazy with little to none input.
The water is so dark that the neon tetras naturally evolved to have such bright colors to see each other.
I can, however, offer advice for obtaining river rocks. Any local landscaping company will buy back unused pallets of rocks and sell them on-site by the pound. I paid 25cents per pound for Tennesee Flagstone (Slate), and close to the same amount (I lost the receipt) for what was labeled as Indian-River Rocks. If you’re lucky you can find some stones that have terrestrial moss already growing on them and if you plant them above water they should spread nicely.
As for your sand bed, maybe look into a nutrient-rich substrate other than sand, rooted plants are going to have a decreased growth rate in the sand. Maybe a soil substrate and a thin layer of sand on top. Or do what the aquascapers are doing and put the soil substrate where your swords are going and make a barrier with rocks and fill the outside with sand. I think a moss wall would look good too.