Hi TaniaPics,
The route you are planning is exactly what got me in to biking..
We didn't do the Xam Neua leg. But did the rest of the loop about 5 years ago..
All very doable.. But you will find the pace a bit slow and a struggle up some of the mountains.
Don't try and over take any trucks unless you can see way ahead.. The wave is just too gutless.
It gets a bit chilly up on the top of the mountains. So have some warm gear easily accessible.
Make sure you wear a helmet and good boots at a minimum.. Extra gear such as jacket and elbow / knee guards would be advised.
Have a great ride..
On the Wave you will take in a lot more scenery and stop for more pics.
Distances in Laos are deceptive.. In the West we say.. 100km, allow 1.5 hours.. that can be 3 hours easily in Laos
Leave early and plan with spare time as a buffer. Not nice riding in the dark. If you arrive early have a Beer Lao Sundowner
Cheers
Brian