Brian
Doable, if you don't get blocked on the E-W road from Tha Vieng to Xaysomboun, and if you don't mind a boat ride.
-- South from Phonsavanh to Tha Vieng, actually just a bit further on, to the suspension bridge at 19-13'-10.70" x 103-21'-22.32", cross over and head west to Xaysomboun,if the let you through.
The Moung Om valley, which you'll pass through, is really nice, pretty prosperous, lots of cattle that they export to Vang Vieng and Vientiane, and probably to Phonsavanh, too.
Towards the west end of the M. Om area you'll pass the Tham Lo Elementary School, large blue sign on your right, at: 18-56'-25.27" x
103-13'-2.04". Note the new furniture in the three-room bamboo school building, our small group from the U.S. funded that for about $2,500. Sunee & I were up there on 29 September just to check on it, looks good. FYI, previously the kids were double-shifting in the ADB funded school building as no furniture in the building the villagers built themselves. Happy now, single shift for school.
On to XSB and RON at the relatively nice Phu Bia Hotel, at least there's hot water, sit-down crappers, and Sat TV (TV not always working). Eats at the morning market. Restaurant at the end of the row of shops is run by the guy and his wife who manage the Phu Bia Hotel, nice folks, but we kind of got in the habit of eating at the place next door to it. Lady there does a good sort of rolled scrambled eggs with onions (khai kuea sai hom hua nyai) for breakfast.
On to VV!
Ex XSB and on to the Phu Bia Mine area at Nam Ngone-Huey Kham-Phu Kham, depending on whom your talking to, this is at the junction to the road on to Long Tieng and the PDJ. FYI, really nice guest house just down the hill on the left from the junction, if you happen to want to RON there rather than XSB. Walk back up to the first eatery on the right for dinner, overlooking the lake to the south.
Then it's 10 km on west to the East side of the Nam Ngum 2 lake. Here's my note from December 2010 trip:
East Boat Landing, Nam Ngum II Lake, Tha Na Tu boat landing, WP 086, 020-380-9052, 020-265-0123, long tail boat, charter for kip 250,000, kip 50,000 to either KM 24 or the Houei Xai landing on west side of lake, about 1.5 hrs ride. Larger boat ETD KM 24 landing at 0900 & 1400 hrs.
Haven't been back since December so things might have changed, but since people do have to go back and forth, should still be boats there. Do go a bit early, tho.
West Boat Landing, WP 078 (18-58.413 x 102-39.702, 1257 ft el), good roads from here down to Rt 13N, just north of Huey Mo.
Note, you can also get off the boat on the west side of the lake at a point near PBM's Houei Xai gold/copper operation. Same roads to Rt 13N.
Be nice if Google Earth had more recent imagery of the area.
Good luck!
Mac, glug gluging it at Klong 10 on Hwy 305 east of Rangsit