Hi i did my trip in Laos,this year in august,and i was consurned about the same problem,althow i rided on this roads,and hadnt expiriensed any problems,except for meeting some guys with civilian clothes and guns by the way to Luang-Probung by road No 13.
As far as i know from locals it is safe now,you can see heavy army presents on those roads,and they dont let rebilians to make troubles.
I know that few years ago were some shooting on road 13,5 km from Vang-Vieng,and about 4-5 tourist been keeled,but now situation chamged and i think it is safe to ride this roads.
Anyway even if you dont smoke have packet of sigarets with you to offer guys with guns,you can make them more friendly.
That what i did when met guy with gun,you never know if it is army or just some hill tribe rebilian.
Take care Bye.