CSTM-Kasara suburban line is also 121 km run one way for many locals daily. On an average, 2-2.5 hours each side run daily. Similarly, CSTM-Karjat (100 km) and Churchgate-Dahanu Rd (124 km), where each ride one way is 2-2.5 hours easily.
If that is possible, then a 140km run from LNL-DD isn't a problem. Moreover no.of stations on LNL-DD as compared to no.of Mumbai suburban stations on each network is less..better running expected on Pune-DD which is a slightly speedy track.