Having played a lot of Mutant I am very exited for forbidden lands, the free form exploration and encounter generation of Mutant in a traditional hack and loot game I think will be increadible. I also loved thr settlement building in Mutant and with every new RPG players dream of taking the fort of the latest baddy and making it a base a possibility in forbidden lands I am buzzing for that. However I just wanted to moot my suggestions for this system and hopefully get a conversation started.
In Mutant I thought town building was a little limited, the culture and technology stats being pretty limited. I emded up house ruling in two additions. Players would each gain a culture point for every 10 points of culture. This represented the resolve to live they gain from actually living in a nice place with religion or a bar ect. They could spend this to add things into the game like many systems or more radically re roll 1s on a push. Regarding technology there was so many ways to gain it I incrwaeed the bands to, 10 20 40 70 and said all gear (not weapons) now give bonus doce equal to your technology rank. I found these changes really helped make town building decisions more interesting making all four stats important and invested players in the town. It was very cool when a radical sect destroyed the temple and god effigy (the blue whale bones in the british science museum) and they lost a culture point. Them failing to prevent it had mechanical and story ramifications.
Anyway obviously this wouldnt be exactly what i wamt put of Forbidden Lands but I would love it if there was various benefits from upgrading a fortress and if those benefits included the comfort and saftey a fotress in a strange land can provide. Perhaps something like the culture system I imagined.