The site needs to be more user-friendly and systemized than a blog, locked to anyone except those who are given access to more than just the homepage. Any tips of providers to start with would be great.
Actually there is a site called the http://www.themembershipguys.com/
They have a lot of advice.
As far as starting a membership site, you can integrate the wordpress Buddypress plug-in with woocommerce or another payment provider. As far as templates, there are a lot out there for membership sites. Without knowing EXACTLY what type of site and more specifics I can't give you a specfic recommendation.
If you'd like, we can schedule a time to chat, and I can get more of a feel for exactly what you're looking for and give you a more targeted recommendation and plan on how to get started. https://clarity.fm/account