How long will this pie keep if I bake it in advance without getting soggy??

I'd agree with Stephanie. Make the pie, as it says and then wrap in saran or plastic wrap well and freeze. When you're ready to bake, preheat the oven and go straight from freezer to oven. Pies make wonderfully this way, please cold butter steams when it hits the hot oven and creates beautiful layers and texture within the pie dough. Enjoy!

You could assemble the pie well in advanced, then freeze it and then bake it from frozen when ready to serve. Alternatively, you could bake it, then freeze it, and then defrost by baking it in the oven so it doesn't get soggy.