Integration Recommendations?

I'm looking to embed my G2 install to give my users more functionality. I'm looking for an integration solution that would give a single log-in, User profile, forum and blog.

My G2 users are using permalinks which use no extra path info - so they work as www.mygallery.com/user I want to retain this functionality. I tried Drupal last year but this conflicted with my permalink set up as it appeared necessary to have Drupal at the root level and G2 in a sub-folder.

I also found Drupal too complex to configure and use.

Can anyone please give me some advice?

Thanks in advance!

DJ