I'm sorry.
Even suggesting she be taken home is frazy. These vets can call the closest vet school, have them look at xrays, consult on treatment, etc. which they should be doing.
It sounds like you aren't wanting to risk it and transport her. Please go with your gut on that. You are right... It may be best for her to be with internists, pulmonary specialists, cardiologists, and oncologists. If this is financially doable for you I would transfer her (not by yourself without oxygen).
When this comes up at the ER here an ambulance service is happy to provide transport. For the right price you coud probably find a medic to take her the 500 miles.