Been living in Pune for 3 years now.
And Pune has lots of serene places around, from hills to beaches.
You might wana come to Pune and book a car and can roam around all of these places (mentioned below) within 100km distance. Hilly places: Mahabaleshwar (my fav), Lonavala, Lavasa, Matheran, Visapur, Mulshi, Tahmini ghat, Pawna lake and many more.
Beaches: Divaegar (my fav), Kashid, Anjuna and others. Note: You can stay at all of these places as there are numerous hotels. Also, you can decide to stay in Pune too and can cover these beautiful places on different days. Hope this helps.