It's only 7 days if we want the special overgrown buildings. (And I suspect those will end up being for sale for gems sometime in the future..). The storyline will remain to do at our leisure. I think I might get the farmhouse, but I'm doubtful about the rest depending on the time limit.
I did buy the new green wisp, spent the gems instead of losing them, lol, but it doesn't have a guaranteed drop of the newborn wisps. So it's going to be slow going waiting on Ivy and a maybe.