In my own Britain crushes the war of independence timeline, Britain doesn't take all of OTL's continental US. The Napoleonic Wars sees Britain and France fighting in North America as well as Europe, the settlement afterwards sees Louisiana north of the Missouri being ceded to Britain. South of the Missouri, Louisiana remains French, although Britain controls the Mississippi and occupies New Orleans (though it remains French). As in OTL, Anglo-French relations improve and Britain and France end up becoming strong friends and Allies. In fact, the Entente Cordiale occurs earlier, helped by Napoleon IV's marriage in 1885 to Princess Beatrice, daughter of Queen Victoria.
Britain then aids Mexico in Iturbide's uprising against Spanish rule. As a result, Mexico wrests all of Central America from Spain (apart from the Mosquito Coast which is British) and turns them into states of the Mexican Empire. Furthermore, the Mexicans desire an empreror from one of the ruling houses of Europe, and naturally they turn to the House of Hanover. Augustus Frederick, younger brother of George VI is crowned Emperor Augusto Frederico I of Mexico. The British alliance and Hanoverian emperor means that Mexico becomes quite a powerful, modern nation with a lot of British influence. Therefore the OTL US states of Californina, Nevada, New Mexico, Arizona, Texas as well as parts of Utah, Colorado and Oklahoma remain Mexican.
The rest of OTL lower 48 US states form the provinces of the Confederation of British America, along with pretty much all OTL Canada and the Bahamas.
As for the other two US states, Hawaii is a Viceroyalty of the British Empire, the Hawaiian monarch acting as a Viceroy/vassal to the British monarch.
Alaska remains in Russian hands until the early 20th century, when it declares independence during 'the war of 1915'.
Basically, like David S Poepoe, it depends on your scenario, you can conjour up all sorts.