Sharing a user-table

Hi, I’ve been using wordpress to manage my personal blog for quite some time and some static page however I would like to move the majority of my web site towards wordpress. My question is how I could implement this transition in the following manner. I would like my website root to have several directories representing a section. For example, https://root.com/log, https://root.com/projects, https://root.com/colophon. I would like the log and projects sections to be able to maintain individual blogs so that I could have a personal blog as well as one for each of my projects. The colophon would just be static. I understand that I could do this using categories and templates but I don’t want to install wordpress in my root directory because of the clutter of files which it would create. Is there anyway for me to use individual blogs for each section and then share a single login or manage each section through a single installation and some combination of .htaccess rules? Thanks for any help you can give me. If you have any questions or need clarification please ask.