I didn't read what was in the link so sorry if any of this is redundant. Both of my dogs have had separation anxiety (newly adopted pup is starting to get over it, I've had my older boy for a while so he's mentally healthy and well adjusted now).
As mentioned, just leave the crate door open all the time, and view the crate as their "room" or their safe place. It is not used as punishment, and it is not used just for when the dog is home alone. Most importantly, coming and going must be quiet, calm, and stress free! So, when you come home and doggie is whining and carrying on in the crate, they don't come out until nice and calm. When dog is jumping and all excited to greet after you come home, turn your back and ignore until she is calm.
My neighbour's dogs have separation anxiety and they can carry on all day long howling and being ridiculous, which makes it very hard for me to get work done. And then they come home and talk to the dogs in the high voice or the excited voice and give them attention when they're jumping all over, thereby rewarding that behaviour and increasing anxiety/excitement about mom and dad coming home.
Start by leaving for short periods of time and extend them. Try crating while you're in the shower, etc. Also, don't let Penny be your "velcro dog" when you're home-don't let her follow you constantly, and encourage her to lay on her own (in her crate, on a dog bed, etc) while you're sitting or doing something, and when you want to cuddle, play, etc, then call her to you. Good luck!