I haven't read the entire thread, but I'll throw in my maxim here for what it's worth:
A woman who is interested in you will move mountains to be with you.
If she says no to a coffee date, it means her interest level is extremely low. Personally, for the follow-up I would say, "Hey, I'm going to "xyz". Why don't you join me?"
If she gives an excuse, she is not interested and you should cut bait immediately. Women like this are to be waded through without looking back. OP, you used the word, "innocent" a few times. The last thing you want is to be "innocent". That is a female trait. You need to be mysterious and dangerous. That's what attracts women. Don't think in terms of an "innocent" date. I'm certain by the way you write that you telegraph a lot of insecurity.
Women should be approached with a light, wispy, fun attitude, as if to convey that you are living to amuse yourself and you might offer her a chance to come along for the ride if she qualifies. ALWAYS BE SUBLEY TESTING HER AND MAKE SURE SHE KNOWS IT.
Women cannot date a man they see as less secure than them and who has less social value. You should be towering above ALL women in your day to day, conveying a slight air of superiority, offset by friendliness and fun.