I think DNN is is ideally suited for use by clubs large or small.  In a way you are on a club site now. DNN!

I use DNN 4.41 for a yacht club in the Hamble.  We have about 2000 members and about 300 guest users.
http://www.royal-southern.co.uk

I use the excellent UCanUse User attribute module to have different registration and user systems for members and guest users.
Other key Modules are Ultra Gallery and Form Master. There are a few Ventrian modules too.
I would have used the core forums module instead of Active Forums but there is no way to show post authors other than by userrname and, for clubs often the best user name to use is the club Membership number as this is also likely to be the primary key on any local system.

I also make extensive use of the most useful DNN module (IMO) UDT. 

For many clubs you may well find that the user Management features of DNN are better (and more secure) than systems used on local club databases. Add a Bulk user manager tool to add usres and export users and you have a very flexible system.
I use Bulk User manager for this.

An important factor to consider is training your admin users  - this can bite you later if it is not covered properly.

I have couple of other smaller club sites too. The clients are very happy and have all saved a lot of money by using DNN.
In effect DNN provides 70-80% of all most clubs need on day 1.

Hope this helps.

Ian