When writing a story, how do you find a good balance between the significance of different elements, such as plot, themes, and bold settings and characters, and the character arcs?
In my case I have a great setting for a minor part of the book, and it is threatening to become much more significant in the mind of the reader than I had intended, imposing its own themes and emotional significance, but I don't want to lose the color it brings to the story.
I am writing a historical novel in which, currently, most of the story takes place in one country (England), significant backstory is set in a second (British Guiana), and significant plot developments happen in a third (France). The British Guiana backstory provides a significant catalyst for why my protagonists meet and get together (he's a naturalist who explores the rainforest there, she lived there in her childhood and attends his lecture about it), and it flavors a lot of the rest of the story and provides a few minor plot elements, but never becomes relevant again as a destination or setting.
I'm new to creative writing, but my instincts are telling me the balance between setting, theme, and character arcs is off. I'd like to give a satisfying ending to those two character arcs. The beginning of the story implicitly emphasizes BG and travel as thematically important because it's a point of connection for the main characters and their families. However, the plot and resolution force the characters to stay in England for the foreseeable future (because of what happens in France), and thus they must abandon any hope of both natural history expeditions and visiting BG. While the lack of further natural history adventures is acceptable and leads to character and plot development, the inability to reconnect with BG leaves me feeling let down, particularly for my female protagonist, who is homesick and might have reasonably expected to travel there with the naturalist. It's an open emotional thread that needs a conclusion.
What needs to be changed to bring these elements into balance?