The first question you should always be asking is not "how" but "why". In other words you should first investigate why you want to make booking decentralized, what is the benefits and what problems are you going to solve? If you can't find good answers to these questions then it is not a good idea to go the decentralized route.
In my opinion, P2P booking is not a bad idea. For instance, it could work a bit like Bisq or Torrents, where you 'host' your offer yourself on your own machine and other peers can see it whenever your machine is online. There are no centralized servers that can be shut down and customers can interface with you directly, so there's no cut taken away by the platform.
That is not exactly P2P though, if there is a single server that is run on your machine there still is a centralized server, it is just not on a third party computer. In torrent network for example the file doesn't exist on a single computer that is why it is pure P2P. But in your idea (same as OpenBazar) if you shut down your computer, the server goes away too.
the true decentralization that Etherium is trying to achieve
You mean the true centralization that ethereum is trying to achieve.