I have read your posts before but I don't think I have posted to you. I would go with #1, call her. At some point, you just have to "know" your situation. Either she will respond, or she won't. If you send a card, a letter, etc., you don't know what her response is. If you call her and she says "leave me alone", you will know that you/she are "done".And you can move forward. If you get an encouraging response, you will know the ball is now in her court and you can go from there.
You have already tried 2, 3, and 4. Did they work? Michelle says "Do what works". If they didn't elicit a response, then go with #1. Is there somewhere else you can call from so she doesn't see your number? I know that sounds manipulative, but then you could stand a better chance of getting her to answer. Then again, if you call from your own phone and she doesn't answer, and you leave a message and she doesn't call back, you would also know she is not interested.......