In short, if you want to avoid Gracie, don't go down the unlit underground tunnel. The rest of the PoI is easy to clear. There are two ways to get the super corn seeds and schematics, one is easy, and the other offers a bit of fun to figure out.
There are also two ways to get to Gracie, the intended path is unlit and is entered from the sub-basement in Carl's Corn (which is through a concealed Steel door), and the proper way/unintended way, which is torch lit with many loot locations.
This last game, I killed Gracie with a level one primitive bow, with stone arrows. It takes a lot of these to kill her. Keep in mind, that the barrier between you and Gracie is just wood (If you go in the proper way), so keep that in mind. If instead, you go down the unlit underground passage, and fall/jump in the hole in the floor at the end, that will drop you right down into Gracies lair, well, I think you and your friend will end up staying for dinner...Gracie's dinner that is.
As for melee/spear, just don't. In general, if you can hit her with melee, she can hit you as well, and...