The Boar War, not 1982 is the apt simile in this case. I would suggest the account in Dreadnaught because the book covers the state of the Royal Navy in the last quarter of the 19th Century. The British military knew that they couldn't supply a squadron of warships or the land forces necessary to hold the islands. During hurricane season the British squadron would have to withdraw leaving Bermuda a day sail away from the American coast. It was an untenable position.
The book Dreadnaught/Dreadnought covering "the last quarter of the 19th century" would be ten to fifteen years off from the Civil War, so it's not appropriate as a source. As for hurricane season, the British used Bermuda as their winter base and Halifax as their summer one; of course, it's not like the Union could exactly hope to capture Bermuda in the middle of a hurricane!
In an actual war there'd be a close blockade of the US coast.
They concluded that it would be impossible to hold Halifax. Without that port there was no way a squadron could maintain itself in North American waters. That isn't my opinion, it is the conclusion of the British command. That port was the only one they had where they could refit.
Citation.
The British absolutely thought they could hold Halifax; the place was both well fortified and well defended.
South of the Chesapeake, there are only a very few deep water ports. Because of that, a British squadron would find itself with wooden ships going toe to toe with ironclads & monitors designed for the coastal waters. That was not a fight they could win.
Really? Name the ironclads and monitors.
For the record, I can name several British ironclads built for coastal waters. The British could also base their heaviest ships out of Bermuda and Halifax, or just coal their vessels on the blockade station.
All of these are, of course, excellent military reasons for not going to war with the United States. In the view of the British high command, it was a secondary issue. Day one of a war with the U.S. would be like whacking a hornet's nest. Hundreds of privateers would swarm out of every inlet along thousands of miles of coastline. British merchantmen would be snapped up in wholesale lots. The blow to British commerce would be enormous.
This is frankly extremely false and betrays a lack of understanding of the true situation.
Firstly, privateering was illegal. The US had agreed to abide by the Treaty of Paris for the duration of the Civil War, and that rendered privateering tantamount to piracy.
Secondly, there were almost no ships suitable for conversion to privateers and almost no guns to fit them, because the existing US war effort had already snapped up all of both. They were even historically taking up sail ships and fitting them with one or two cannon, and had none to spare; an effective privateer this is not, not when so much of the British merchant fleet is steam.
Thirdly, the British had successfully protected their commerce in 1812 with the use of convoy; there is no reason the same would not happen here.
And fourthly... name the ports. The British planned for blockades on the mouth of the Chesapeake, at the mouth of the Delaware, in New York Bay, covering Long Island Sound, at Boston, at Portsmouth and at Portland; out of where are the privateers going to "swarm" where they won't promptly run into a blockading force?
(For context Boston had exactly one coast defence gun; if you divert guns to fix that you're not fitting out privateers!)