Hi again and thanks for your reply.
You provided a lot of information in your question, which is appreciated, but you said your main problem was how to get her to the vet. If you already know about mobile vet services, why don't you call one in your area, and that will take care of the problem of getting her into the carrier, etc. If you can't lure her out from under the bed and you know the mobile or housecall vet is coming, block off all under and behind areas of furniture, so she has no place to hide. You can set up her cat bed in a quiet corner, so she feels more secure and put an old t-shirt with your familiar and comforting scent on it, in the bed, so that makes her feel better, too.
If you didn't know about Clomicalm, discuss this, and other medications in its class, with your vet, and see if she's a good candidate for that.
If there's anything more specific that you need information about, because I did my best to address all your concerns in my initial answer, please post back and let me know, so I can help you and your kitty further. Thank you very much!