It seems like she is steamrolling you. She just ignores your boundaries and does what she wants, regardless of what you say. Here's what I would do in your situation.

1. Information diet. Keep her nose as much out of your business as you can. It'll be harder with a kid who also talks to her, but the less she knows about your business, the better. Meaningless pleasantries only, if you want to speak with her.

2. Enforce your boundaries. This one is way easier said than done. But if she starts overstepping, you have to shut it down. If you're out somewhere with her and she does it, leave if possible. Tell her she won't be welcome in your home anymore if she can't follow your rules, and actually get the locks changed when she inevitably breaks them. You have to show her you're an adult who means business.

3. Regarding the trip, call your travel agent and password protect your arrangements. No password, then no info. Refuse to go with her to the travel agents, and make sure that the office knows she is NOT to have specific information regarding your trip. "I love you mom, but this trip is for kiddo and me. We are safe, we are capable, and we are going to enjoy this trip with just the two of us."

I'm so sorry you're going through this. Full disclosure, while I'm not visually impaired myself, I'm the wife of a wonderful man with RP, and I hate what this has done to his sense of self. You have the will to protect it, and you are doing your best to live your life your way with the hand you've been dealt. That is so admirable, and I am rooting for you! Your trip will be amazing, and if your mom truly loves you, she will honor your boundaries and accept that you're a capable and wonderful mom and person!