A ``Windows Installer'' program can install a complete ACL2 environment on Windows. If you care to volunteer to build it, you can can volunteer; send email to Matt Kaufmann, who will be happy to send instructions.
However, you can probably do fine if you obtain a Windows installer for a previous ACL2 release and then follow installation instructions for building the latest version in the resulting environment (which mimics some of Linux and provides Emacs).
As of the date of this release, we expect that before long you will be able to fetch a corresponding version of the ACL2 Sedan. That software includes an ACL2 distribution that can be very convenient for Windows users. Also see the ACL2 documentation topic on the ACL2 Sedan.