Unity VR google cardboard VR deployment

Hello. My name is Milos Radulovic and I'm an architect, who is starting to experiment with VR presentations of interior design (solutions). I've used Unity for couple of years to create " desktop, mouse and keyboard " walkthroughs while working in previous company, so I have OK level of knowledge regarding Unity (admittedly very narrow). My latest client asked me if it would possible to show her my latest solution in VR. She doesn't have Oculus, Gear VR or Vive so only remaining solution was Google Cardboard, which is, thankfully, covered by Unity. I'm almost done converting my scene into Unity VR project, but I have a question / problem - how to easily deploy the file so she can use/see the VR file on her phone using Google cardboard? SO far, all internet links point going through Google play store. This seems like a bit of an overkill, since I'm not making a true app, but just an VR walkthrough scene. My question is - is there an alternative to Google Play Store or what would be an easiest way for me to deploy my VR scene to my client?

Thanks in advance Milos