Open your ideas to vignettes that will please the child or children and you. There is no rule that states that each module must relate to the next. View each module as an opportunity to create a scene.
Many apply the same approach of a fixed layout to a modular layout. That appears to be what yours was originally. While that looks great, and the layout is portable, there is a lot of fun to be had if you inspire your imagination.
Roger Farkash and TWTrainworx blend realism and imagination wonderfully. Check out this layout for BNSF corporate, which had to include many of the elements of the entire operation on one layout.
Search "modular layout" on the forum to see what others have done. Do some web searches too.
The remote Thomas by Lionel is very popular with the children as reported by modular clubs that set up at different venues. Gives the visitors a chance to participate. Accessories with buttons for operation on the outside allows the visitors to participate also.
No matter how you scenic it, have fun ! You have a fresh palette and a different perspective after some time has passed.