Thanks for your replies, fellow PW developers – that's really great. The bootstrapping of PW and custom logins are good starting points. After a big delay I am back again wrapping my head around this and getting to know PW better. Awesome CMS to say the least.
I think my project is going into a direction where i would host the basic pages (login, logout, dashboard, some DB listings, search masks and forms) within PW. To clarify my question there's for example an existing "/dokuwiki" (www.dokuwiki.org) in a subdirectory of my root on the webserver with a lot of content already functional in place. At the moment this is secured by means of a .htaccess file. Quite possibly the project might incorporate other subdirectories with other on-its-own applications. Now my questions are (sorry, if they are much too "basic" at first sight):
Would it be possible to manage such an existing on-its-own application in an existing subdirectory within PW? By "manage" I mean just basically have it "sitting in there" and link to it from PW (or if not at least "hard coded" inside the HTML template). And also not interfering with PW's URL rewriting for pages.
As for user access permissions would it be possible to manage this within PW as well? First of all the simple case of a user trying to access the /dokuwiki directory.
Since "dokuwiki" has some user management built in already, I guess the capability of "forwarding the access permissions" from PW to dokuwiki (letting the user just read or also write) is dependent on API interface of dokuwiki, right?