I've followed the developer videos at Umbraco.TV  All the examples revolve around augmenting a project that contains the entire Umbraco framework.  I want to access an existing Umbraco installation from a different project installed on the same server.

Are there any tutorials showing how I can reference the Umbraco.Core dll then instantiate that using the URL of an existing Umbraco installation?

An alternative is to create a bunch of web API services inside my Umbraco installation then access those from the other project - I think I know enough to do this already but using the method above might be simpler.

The key point is to end up with many projects all accessing the same Umbraco installation.

I know I can have as many Umbraco installations as I want all with the same connection string but that's overkill - I want to know what the "lightest" configuration is to create and get Umbraco content.  If the web API route is the best bet from architectural and security perspectives then that's fine.