It is common practice for simple sites and implementation to just use one project for the public, member and admin sites.
You should be able to section each area depending on user permissions so there is no need to create two separate websites.
I would suggest the following resources for best practices and examples.
- Nerd Dinner (code is hosted here)
- More best practices
And the best place to start MVC pages at asp.net
There is also a ton of questions and community wiki entries on Stackoverflow about best practices and website layouts.
Hopes this helps