hmm imho, your friend does pose a problem
you both sailed in a ship that sunk and you've found/made yourself a liferaft - she has just got he head back up above water and a liferaft looks mighty appealing. Thing is, does she want you to help her make her own (very worthwhile and honorable thing to do) or does she want to cadge a lift in yours (oops - not such a good idea)
Way I think is - she knows where you live (Xmas card sending) and if its the latter, she'll turn up anyhow probably so is it not best to control the direction of any contact ('hi, welcome to fresh air, lets meet at X, here's the tool kit for building a liferaft, shall we go and find some wood and nails and we can make a start' rather than 'oh, what a surprise, come in and have a cup of green tea, where are you staying now?'
Hope you don't mind my butting in like this but I always like analogies as they can sometimes help put a different focus on matters (if used well - and there's the test of my post - does it make sense)
Bon Chance
Mindless