When you load a community in OuterSpatial iOS or Android, the app downloads an index of information to drive basic functionality even when in no network or bad network situations. This primarily includes the information needed to drive the "Explore" functionality in the app, including the map, list, and search tools.
This is why the initial load of a community can take a little while. Subsequent loads of the community should be much faster.
In the future, we plan on adding support for explicitly selecting one or more locations (areas, trails, outings, and/or points of interest) to download for offline usage.