Hi Hartofglass,
I'm sorry to hear your father passed away earlier this year. It does sound like you are very aware of your situation and have made great progress in healing from the influence of a BPD mother.
You said

“now I'm finally free of the FOG.” and your father has passed on, you want to move. Which makes complete sense. But If so , why do you seam apprehensive of moving ? Especially when you say

“Even just the thought of that makes me so happy.”
Your predictions on how your mom will react sound about right for someone with BPD. But as their worst fear is abandonment, I guess anything you can do to lessen that will help. But as you are aware your mom will start a campaign, short notice might make it practically easier for you. But what do your husband and children think about all this ?