I think I would want her on muscle relaxers along with the pain med, and keep her from getting too cold so she does not tense up. You may want to raise her food and water bowls if needed.
Here is some information on crate rest for a neck problem.http://www.dodgerslist.com/literature/cervical.htm
Yes, I would think there is a lot
of hope. I would be optimistic. She did improve, she just had a setback from too much activity. I would keep her restricted. Crate rest isn't fun and it is easy to feel sorry for the dog, but a few weeks in a crate is a small
price to pay for a lifetime of walking, so you need to have tough love and insure she doesn't set herself back again. You're not being mean, you are doing what's best for her. Especially with a neck problem, you do not want to risk further injury until it has time to heal. It is so tempting to let the dog out once she looks like she has improved, but the results can be like taking a cake out of the oven too soon. It might have looked done when you peeked in the door, but you soon find out it wasn't. She might think she's better in a week or two, but I would follow the guidelines as shown in the link above, which tell how long to continue crating.