Just how big of a wall print can I make with various Sony cameras?

So I'm looking at getting a Sony Alpha 7R V but am thinking perhaps that is overkill for what I want to do. I'm not a professional photographer but do a lot of backpacking/trail running and coaching of runners. I want to be able to take epic landscape pics but the heavier the camera the less likely it is to come with me when I am say trail running or backpacking. For coaching scenarios it can be larger but the majority of my focus is on coaching and I do a fair amount of running around the course and sometimes snap photos. My phone camera just doesn't cut it though I get good pics, just not something I'd print out. I want the really high quality pics but also want something lightweight but whenever I compare cameras don't know what I'd give up in clarity and quality when I go down a size level. I've also looked at using something like topazlabs gigapixel in order to take lower quality pics that are still decent and upscale them in order to print something memorable but haven't used that before either.