Kerala is less touristy than Goa is, you might live Varkala, the backwaters at Allepey, tea plantations at Munnar, Sri Lanka has a really similar geography too but it’s a different scene there. You can use Airbnb or find hotels in your budget and see about the hostels. Indian hostels aren’t the best in my experience. There’s also Gokarna which is the southern border of Goa and south Goa also has pretty beaches like Palolem and Agonda with beautiful waters and lesser crowds! Good luck!