Advice on approach to setting up a site to produce custom cookbooks

I have a client who produces custom cookbooks for organizations.
They started with a simple form where the user submitting the recipe just selected their organization from a list. Now they want to go to the next level and have some ability for the end user to manage their own submissions. I could see three basic approaches and I am looking for advice or opinions on which way I should go.
1) 1 page for each group that is password protected on the page is the submission/ordering forms and a section further protected with an admin password to see their list of submitted recipes. Seems pretty simple, and easy for the client to add a new group (just copy the page, and change out a few pieces) but it really doesn't let the operation grow and morph as these kinds of things tend to do!

2) (The approach I am currently pursuing) Using the membership plugin to control access to the pages which elevates the whole perceived professionalism which in part is the goal of the client. However, to set up a new client, they will have a slightly larger handfull of tasks to do (replicate pages and set up a new membership level etc) and I am not so confident in their tech savvy on this part. However, it does give us some room to add additional functions at the group level for future evolution.

this is what is making me wonder if I should approach it from the WPMU perspective (I haven't worked with WPMU before, so it makes me nervous and I don't know if it is massive overkill and unnecessary complication)

3) I could set up a wpmu network for the client and give each group and unique site. I could use wpmudev plugins to automate the client site set-ups which may be easier once they learn how. But then you run into problems if you want to have some base content (Generic info about putting together a cookbook etc) You could have the pages as part of the auto set up for the custom sites, but then you couldn't do a system wide update to the content (unless you could have a "parent-site" that they access through the groups custom site?)

Any help, suggestions, or considerations would be gratefully accepted!

I am using gravity forms to submit the recipes and the Gravity forms directory add-on to display them on the front end. One of the main reasons I am using gravity forms rather than a custom post type is the need to export the submissions into a csv file. So if someone has an idea on how to do that from a custom post type, I would love to do it that way!

It just occurred to me ... would BuddyPress fit in here somewhere?