One of the things you can look at is git-cvsserver. I last worked with it about 12 years ago, but here are the basics. You can convert the CVS repo to git, then let the users point CVSROOT at the git-cvsserver. This allows them to continue working as with CVS except git is the backend.
As you have time to train the users for git, you can then transition their workspaces to use local git repos. it is also handy if your build system is set up around CVS.
This is mostly a transition tool. For the users to get the benefits of git (speed and power) they are going to have to learn to use git.