Yes, sounds good!

NO, 'map out' is related to maps (metaphorically) so it's not suitable for any decision. You could map out a plan for a trip, or a schedule for different days, or ideas for an essay (things that you can link together on paper, maybe). You can't say 'map out alternatives' for normal decisions. It doesn't make sense. 'I rarely bother to carefully consider/think about all the alternatives...' or 'I rarely bother worrying about all the alternatives..' would be better. :)

Since the word, alternative means a few or several choices, saying, "a few alternatives" sounds redundant. Instead of saying, "I rarely bother to map out a few alternatives when I make big decisions", I would say, "I rarely bother to map out alternatives when I make big decisions". or preferably, "I rarely bother mapping out alternatives when I make big decisions". Hope this helps