A travel-insurance policy to cover theft, loss and medical problems is an excellent idea for travel in Nepal. There are a wide variety of policies available, so check the small print carefully. Some policies exclude ‘dangerous activities’, which may include riding a motorbike and trekking (and definitely bungee jumping and rafting).
Choose a policy that covers medical and emergency repatriation, including helicopter evacuation for trekkers and general medical evacuation to Bangkok or Delhi, which alone can cost a cool US$40,000.
You may prefer a policy that pays doctors or hospitals directly rather than you having to pay on the spot and claim later. In Nepal, most medical treatment must be paid for at the point of delivery. If your insurance company does not provide upfront payment, be sure to obtain a receipt so you can reclaim later. Some policies ask you to call back (reverse charges) to a centre in your home country where an immediate assessment of your problem is made.