Budget-Friendly Pre-Production & Visualization: Seeking Advice

Hey everyone, I'm Marcus, a writer/director, and I'm currently wrestling with pre-production on a short film, a character-driven thriller. The typical advice often champions things like 'story summits' and extensive pre-visualization with high-end software, which sounds amazing, but frankly, it's just not in the cards with our shoestring budget. We’re talking coffee shop meetings, not mountain retreats. I’ve tried sketching out storyboards myself and using free online tools for shot lists, but it feels like a very solitary process, and I'm missing that collaborative spark. How do you all approach visualizing and collaboratively finessing a story and its execution when professional retreats and expensive software are out of reach? What are your go-to low-cost, high-impact strategies for pre-production?