You are required to take the breathalyzer but can't be compelled to take it, they can't hold you down and make you, we agree, refusal to take it adds to your suspension time if you are convicted. And as you say you can still be convicted on the officer's observations. As people were in olden days and can be convicted for pot intoxication, for example. Reckless is a heavy lift, it requires almost intentional conduct as opposed to careless which is driving w/out due care in a manner that endgangers people or property.
And an interesting side note, even though this is Federal land, at least the reckless is a state charge. There are no Federal ordinary driving statutes. Under an Act of Congress: " if a criminal offense under state law is committed on federal land, and there is no chargeable federal criminal offense, federal law enforcement and federal prosecutors are authorized to charge offenders in federal court for a state law violation. " One of the most common is DUI, but: "Whether DWI/DUI is charged under [state] law or under the federal DUI regulation will depend on whether the property is operated by the National Park Service. A federal DUI charge is a class B misdemeanor...." Ok, this is already getting too complicated, seems Sandy Hook is a National Park. But the proof needed should be the same.