How to care for my dog with lung cancer?

When I went to the vet last week, I was told the worst of news. The vet tol me my dog Ginger has lung cancer and she can't be opperated. She told me to pamper her as much I can and make her feel good until the time comes where I have no choice to... So, to get to my question, My dog is now very much out of breath all the time, even just lying in bed. On the other hand she loves going for walks, and still has the energy to whine to go outside, but I don't know if it is worse for her to walk and exercise or just relax and do nothing. If anyone has been through this before, please let me know, all I want is what is best for my baby. thank you.