Expect a lot of yo-yoing on her part. Do not expect her to come back, and don't misread those good times for anything more. A nice note, "It was fun seeing you! Take care..." will encourage friendship, but don't write much more and definitely don't expect a response from her.
Think of it like trying to tame a wild animal. You have to give without expectations. You lose nothing in giving and perhaps at a future date, a good friendship will bring you closer... and maybe not. But anytime you reach out and try to take hold, even for a moment, you are going to scare that animal and it may take a long time for it to feel safe again, or at some point it may get too scared and leave for good. It needs complete freedom. And when it comes down to it that's really what you want to give because the choice for more interaction should be the WAS.... I hope that makes sense.
One way I used to look at it, was I just wanted to create positive memories for my H (who had been divorcing me at the time). Every little drop in the bucket is one more. You want to be the "place" they feel comfortable going to, where they feel safe and where they may eventually want to be. And then again, they may never want to come back. (My H sure was very determined to never come back!)
And if they never do, you'd like them to at least eventually look back and think; hummmmm it wasn't so bad. In fact, I left something pretty darn good. Boy, I was stupid!
There is no arriving, ever. It is all a continual becoming.
