This example shows one strategy for dealing with very big grids.
The basic idea is to have all your data in a big grid, and the cells that make up the visual presentation in a much smaller grid (that just covers the screen). The small grid is then updated as the player scrolls to simulate scrolling of the big grid.
This example assumes it is fast to update visual cell information from the grid data. If it is not, you may need to implement more measures (such as updating in the background, or moving only edge cells instead of updating the entire grid).
To run the example, download it, and import grids and the package into a new scene. The example is in the ScrollingGrid scene.