Have you seen Open Work Bench www.openworkbench.org
? It's freeware and claims to be a project manager.
I was looking for something that would be useful (I'm thinking of having a house built) and that would not only help with the planning but also keep track of expenses - over or under budget with various trades, etc.
I've downloaded and installed it, but it's a bit too arcane for me to use straight from the box. You may have better luck with it.
The forums are hopeless for Open Work Bench,IMHO, as they are clogged with spam.