I can't remember how I came upon GWTP, but I am sure glad I did. GWTP provides an additional level of structure, abstraction, and code generation that makes it much more enjoyable to build GWT interfaces and (more importantly) connect to back-end service/data providers. 

But like any framework there is a learning curve. I learn best by example, so over the last months, I have been searching for practicals tutorials and examples. The two best resources I have found to date:

1. Dani's YouTube video series on GWTP http://www.youtube.com/watch?v=Gm-RO-cmsEQ
2. Uptick tutorial and working application http://uptick.com.au/content/gwt-login-security

There are many more great resources for GWTP (including the project site), but I found these the best at getting started and then diving deep into the inner workings of a real application. Many thanks to the authors of GWTP, Dani, and the folks at Uptick!