I know you asked about NJ/NY for a POTS specialist, but there is one in Johns Hopkins in Baltimore
, MD named Dr. Peter Rowe. His treatment
protocol is available online, including the salt/liquids that you mentioned, but also drugs like Florinef. However, I've ready elsewhere from a chronic fatigue doc (Dr. Paul Cheney) that Florinef can stop having therapeutic effects after 6 months so he advices against it.
You mention your daughter tried alternative medicine.