When you need hotel advice always mention a price range. Khao San Road is popular with kids and young travelers - if you are in that category - go for it!
But, there are other areas of Bangkok you can stay at that where you can also find budget hotels and use the overhead rail service too.
If your flight arrives so that you can use the Airport Rail Link (closes at midnight) you can get from the airport to the Pratunam area for only 45 baht using City Line.
From Pratunam you can either switch to the Skytrain at Phaya Thai or take a meter taxi to your hotel. There are even hotels you can just walk to from Phaya Thai or Ratchaprorop.
My preference is the Sukhumvit Road area because you can find hotels in all price ranges and also use the Skytrain. Also, many malls, street vendors, cheap restaurants, travel agencies for tours, nightlife and supermarkets.
There are other hotels/hostels not far from rail service.