"I wonder what the distance will be before it becomes as visible as our moon in terms of how much real estate it takes up in the sky. "
It is actually pretty easy to calculate knowing it's diameter, distance and apparent size, but I am too lazy to do it :)
Guess you already read it, but most likely Solar system won't be affected by the collision. and time and duration of the collisions depend on different models in simulations.
RE: Beautiful Corner of the Universe - The Andromeda Galaxy