Scrips are definitely not the easiest. You want a 560 gathering set since this spiritbonds faster. Meld as much perception as you can to try and reach the 3600 requirement (You can use 590 scrip tools and perception food to make this cheaper). Pentameld the rest of your slots with the cheapest low grade materia you can find (this increases Spiritbond rate). Use a Superior Spiritbond Potion (you just need +5 to cap it, any more isn't necessary).

Aim for max gathering attempts on Legendary nodes, using Ageless Words/Solid Reason + Wise to the World.
You can follow this route for the current Legendary nodes.

BTN 12:00 (Thavnair, Yedlihmad/ Palaka's Stand)
MIN 12:00 - Garlemald - Camp Broken Glass
MIN 2:00 - The Moon - Sinus Lacrimarium
BTN 2:00 (Elpis, The Twelve Wonders)
BTN 4:00 (Labyrinthos, The Archeion)
MIN 4:00 - Elpis - Poiton Oikos
BTN 6:00 - Elpis - Anagorisis
MIN 6:00 (Garlemald, Tertium)
MIN 8:00 (Moon, Bestway Burrow)
BTN 8:00 - Thavnair - Palaka's Stand
MIN 10:00 (Labyrinthos, Aporia)
BTN 10:00 - Ultima Thule - Abode of the Ea
Keep in mind all the gathering bots do this too, so while gathering materia shot up at the start of the patch, prices are crashing again and likely to continue doing so. It might be more worthwhile to buy some.