re: Boss is retiring - don't want her job

I get that you don't want that gig. But the question you need to ask yourself is would you trust someone else to do it (and be your boss)?

If you care cool with that, don't apply and then when they ask, tell them you did not anticipate the compensation would be worth the additional responsibility. They might up the pay and make it worth your while.

If you think about it, I'm sure you can figure it out.

Tell your superiors that you aren’t ready to take on that level of responsibility at this point in your life

If you have the opportunity and don't apply, they may think of you having no ambition and a promotion to something better might not present itself again. I agree with what others have said. Apply and make them pay you an amount you honestly feel it's worth. Just keep looking for something else and enjoy the resume boost.

Honestly though, if it's something that would make you miserable you should be looking for another opportunity outside that company any way.