It is. The main tourist centers like Pokhara, Chitwan and Lumbini are connection by good roads and all main routes are well serviced by tourist buses. However, roads to other towns for example Jiri and Dhunche are steep and narrow and only local buses are available. We advise you to hire a private jeep (4WD) to travel these roads safely. Typically tourist buses are driven with more care than local buses.