tell her that you think she's swell, and if you think shes cute, tell her you think she's cute, but long distance relationships are too difficult for you, and reasons why you dont want to do a long distance.
also remind her that you don't think its weird or awkward or anything, she's still a cool girl and it would really really suck if this caused an issue between you two.
you wont crush your heart as long as you explain exactly how you feel exactly and say you still want to be buddies. this kind of stuff will happen to you multiple times in your life, and me saying that kind of stuff to guys (except telling them why i dont wanna) has usually made them understand... just kind of explain you're still interested in being friend and the fact that she likes you as more than a friend doesn't make her less of a friend to you :)
after reading your 1st topic, keep in mind she may or may not actually love you, she just NEEDS you. you need to be supportive and gentle and let her know that you need her too (i'm guessing this is a kind of mutual 'problems in my life' friendship, but hers are worse than yours?), so she won't fly off the handle and potentially hurt herself