By this point, neither side is likely to press hard for the war to continue.
It's become pretty that America won't be able to annex significant Canadian territory, and with Napoleon defeated, impressment and neutral shipping rights are no longer pressing issues. With a tightening blockade on the American coast and with British troops from the Continent now available to be deployed in North America, status quo ante bellum is looking pretty good from the American perspective.
Meanwhile, while Britain has the theoretical ability to continue to press the war, they're pretty war-weary from years of fighting Napoleon, and the value of potential American concessions to Britain is limited relative to the cost of compelling them: Britain would rather demobilize troops, scale back wartime taxes, reopen American trade, and husband their remaining military in case things turn ugly again in Europe, rather than spend huge amounts of blood and treasure trying to conquer a significant chunk of the United States.
If Britain succeeds in sacking or occupying Baltimore (I'm not sure which was the objective), I'd still expect a peace treaty later that year. America's negotiating position will be weaker and Britain's stronger, but not by an overwhelming degree. I'd expect the final treaty to settle the US/Canadian border a bit more favorably to Britain than IOTL, but I don't think Britain's interested in continuing the war long enough to compel major territorial concessions.