So happy it's going so well! You probably noticed from my reply that I spoil the f*ck out of our girl, and go way overboard on things. Fair warning that people have big opinions about Danes, even when they don't own one. If one more person says "you know they don't live very long, right?", I'm going to lose my mind.

Crate training can be ROUGH. We had better luck when we started putting a blanket over it. I eventually got one of these covers. I liked that it could roll up on all sides. It's silly but I also just liked that it looked more neat and clean. https://www.mollymutt.com/for-crates.html

The clingy-ness is just a Dane thing too. I'm still working on that. I was so focused on her being socialized and trained, that I unfortunately didn't put enough time into her being independent. It's wonderful you're already starting this! We took pics of her sitting on the couch near the corner, it was easy to judge the growth with that. We also took pics of her laying next to our big fat cat. Her head is about the size of his body now. For the booties we just straight up bribed her with sugar free peanut butter on a spoon, started with one at a time and after a couple weeks had all 4 on with no peanut butter needed. She still dislikes them, and gets cranky about it but she'll tolerate them.

For the car- I recommend a dog seat belt. For a travel crate my husband used one of these for the back seat of his truck, she grew out of it around 7 months and now uses the dog seat belt in both of our cars. https://www.amazon.com/LIOOPET-Portable-Folding-Indoor-Outdoor/dp/B08WYSRH25/ref=sr_1_27?dchild=1&keywords=dog+crate&qid=1619551742&sr=8-27

For planes, our girl isn't certified as a service dog and with all of the airlines cracking down on companion animals riding in the cabin, we haven't looked into it much. I'd love some suggestions if you end up taking your girl on a plane. I'll eventually throw her office bed in the car when we start camping/traveling to family and friends again. We just use a blanket at the park.

Random unsolicited advice:

Home Depot is a great place to work on leash manners and training. It's dog friendly, noisy and busy. Perfect for training with distractions. Bonus for the AC during the summer. Most of their employees even carry dog treats!

Sorry for the lengthy response! Good luck, and I hope you get some sleep soon!