How would you approach this project?

I'm developing a php web application that draws inputed data from a series of online forms.. and distributes it to:
1. an online database - with attached CMS to view data.
2. A document generator that produces .pdf and .rtf documents from inputed data.

What platforms would people recommend for this? Entirely custom built web app?
The client is familiar with wordpress - not sure if it's possible to use this CMS.

Help!