That sounds like a perfect project! First, get a solid plan—draw out the fortress, mark the measurements, and make sure every joint is double‑checked. Use hand‑sanded pine for the walls; nothing beats the feel of real wood over plastic. We’ll weave the vines through the frame for natural insulation, but keep a weatherproof sealant on the seams so the moss doesn’t get a foothold. I’ll pull out my old toy treehouse kit for reference—old tech is always the best research. Just remember to leave a little exit for the squirrels, otherwise you’ll end up with a full‑time squirrel headquarters!