there is a roadmap on the mod page itself (the tech tree), which highlights some of the key unlocks in each science pack (and if there are science packs missing, which version it'll be in) - i talk more about whats planned specifically in the discord server if you'd be interested (which is also on the mod page)
I'm not doing space age compatability, it was thought about and theorised but i essenitally have to beat space age into submission to make PM fit inside of it, but i will be making a space addon to PM that uses all of the DLC features