Absolutely, "Kudos" as above, and yes, teach her that these things are safe. Suggest pinning the door to her crate open and putting her water or meals inside the door, just to where she has to put her head in but not her whole body. As time goes on, move the food and water further back and let her get used to the fact that it isn't a prison but a comfy place to visit. This is presuming that you are not confining her to a crate to start with.
If she comes to you with crate problems and you don't want to crate her at night and while you are at work, use a baby gate to section off one room, like the kitchen, which usually has tile floor, so messes (every dog has messes) are easy to clean up. If there is a mess, let the dog out to use the yard (if fenced) and clean it up without incident. If she's timid, perhaps past accidents have been met with harsh punishment.
Leashing: Was she tied up or was she uncomfortable being leashed or had little or no training being walked? I've heard some members say that leaving a harness or leash on in the house helps them adapt to it not being a threatening item. Walking the dog in the house or yard with the leash and being patient while they figure out it isn't harming them may be what you need. Personally, I went from a lead to a nose-type harness which causes pain if they pull, to going to a chest-type harness which limits the amount of pull they can exert while keeping you in the driver's seat, so to speak. The harness has been a blessing.
Cars: Don't feed the dog within an hour or two of driving. Less chance of them throwing up. If they want to lie down, let them. If they want to sit on a seat with their paws on the floor, let them. If they want to sit in the middle looking out the window between the driver and passenger seat (I have a van) let them. If they pace and wail and act out in the car/van/truck... either crate or secure them with a dog-type seat belt or harness. Personally, I don't like letting our dog into the front passenger seat, I feel it's more dangerous, and it is a distraction. Eyes on the road for everyone's safety.
Sleeping: I've often heard it said that CC's in particular like to be in the same bedroom with their owners. And with ours that has been very true. And she wants to be on the bed. Originally there was a large crate in the corner of the room decked out with comfy padding and blankets, but she didn't want that, she wanted to touch skin with us, be up on the bed with her mommy and daddy. HAVING SAID THIS: It is a choice, but once you make that choice...It's for life. Husbands in particular hate this one...oh they love the dog, they just hate sharing the bed with another big, sprawling, snoring creature. They snore and sprawl enough without competition. Husband is snickering at this one! So True!
Other Dogs: CC's often come from very large litters ( ours was from a litter of 15) so they start off knowing how to be social with other dogs, keep that ability! Really, make time for her to associate with other dogs and to make dog friends in the neighbourhood. If you are of the opinion that dog parks are a good thing and are willing to go that route, first establish a rock solid recall. You call and No Matter What, She Comes. If you've got that, take her there and let her see it from the fence first, then inside on a leash, then meeting with a few dogs, then, IF you feel it is a good park with good people, let her have that strength that comes from being in a large social group. Note: Not everyone has a park that is well run with good and well behaved dogs and people, so, it's really a roll of the dice if there is a good one in your area.
Otherwise, come back here to the Forum and ask as many questions as you like, we are here to help you. We don't always agree (I can guarantee that) but you will get a cross-section of advice from across the whole realm that is Mastiff. And Blessings on you for rescuing that girl...every Mastiff deserves a second chance with a good pet parent.
