Since it's already early morning in Pune, plan a relaxed start: take a mid-morning local train from Pune to Mumbai/Chhatrapati Shivaji Terminus and then an onward suburban train (or a pre-booked taxi) to Neral; aim for a Neral arrival by late morning so you can buy Matheran toy train tickets or the shared jeep/taxi to the boarding point. On arrival at Dasturi or the Neral point, board the charming narrow-gauge Matheran toy train (if running) or take the short pony/foot ascent to achieve the hill-station vibe, stopping at Panorama Point for sweeping views and photos.
Spend the afternoon wandering Matheran's car-free lanes: have lunch at a local restaurant near Charlotte Lake or at one of the cafes on the main market lane, then walk to Louisa Point and Echo Point to enjoy open valley vistas and the cool breeze. Include a visit to Alexander Point and Honeymoon Point if time and energy permit — these are gentle walks with excellent lookout spots for sunset planning.
As evening approaches, head back to the market area for tea and snacks, pick up some local chikki or souvenirs, and make your way to the Matheran boarding area in time to descend to Neral by road or the late toy train (check the timetable). From Neral, catch a suburban train back toward Pune or a train to Pune via Mumbai connection, keeping buffer time for transfers — you'll arrive in Pune late evening with memories of a peaceful, car-free hill station day.