@AndrewWatkins I’ll look into this.
I have worked with rough sawn lumber several times. You need to be sure it is dried sufficiently to stabilize the wood. If not you can invest a lot of time in a piece that can twist and split. Commercial lumber is normally kiln dried but you can air dry it if you are willing to stack it properly and leave it for several years. The comment about salvaging solid wood furniture does work well but you will probably need a planer. If you need wide pieces you will need a biscuit jointer and clamps to glue up a wide, stable piece.
I use ocooch woodworks, They have wide variety of hard and soft woods, scroll saw ready meaning sanded on both side or roughcut. The best thing is you can order in all different sizes up to 8ft boards
Peach Tree out of the Atlanta, GA area, is a good source.
Hibdon hardwood St. Louis area
Gilmer Wood Portland, OR
Cook woods (somehow I got on their mailing list, but have no experience with them)