The road situation which I have been able to find out is as follows:
(1) The Saser La is route to DBO is the summer caravan route which was used in earlier times as crossing Shyok river in summer was a big issue, not to mention life threatening.
As per a 2008 report by an expedition which took the Sasoma-Saser La-Saser Brangsa-right bank of Shyok river route to reach glaciers at the starting point of Shyok River, Indian Army had constructed a road from Sasoma to a point just short of Saser La. The expedition report talks about seeing bulldozers in general area of Saser-La. However, there is no known report about BRO/IA having COMPLETED this road. In fact, some time back when this whole DBO incident flared up, there was a small reference to this communication axis and the fact that BRO has not been able to make this road fully operational.
For reference - please see the map link below
The map is centered on a series of bends in the mountain range to east of Sasoma Camp. You can clearly see that a road has been cut into the mountain side and if you follow this road, you can make out a road till the point from where ascent to Saser-La actually begins. Regrettably, the map for exact Saser-La area seems to not have been updated by Google and the presence of snow in that area does not allow to ascertain presence of a road on the map. If one starts to look up from the other side (Shyok River to Saser-La), again, the area is covered with snow and one cannot make out the presence of a road. Though, some trails are visible.
You would be quite amazed to know that private tour operators organize trekking camps from Nubra to Sasoma - Saser La-Saser Brangsa-Murgo and all the way up to DBO and KK Pass.
Here, check the trek itinerary from one of the operators. Has some good photographs as well:
(2) The second route is the winter route when Shyok freezer over.
Rather than me going into details about the route, please read this excellent account of a trekking expedition in the region in 2002. The expedition went from Shyok Village (at the V bend of Shyok) to KK Pass, then traveled west along Chip_Chap River and crossed into upper Siachen after crossing Remo Glaciers, Col Italia and Teram Shahr Glaciers. It has a very good map explaining the route and features.
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The map is shown below:
What the above report tells you is that a road existed even in 2002 between Burtse and DBO. And further, from DBO to Gapsham, where the Chip_Chap river meets Shyok River.
This expedition in fact clearly shows the strategic nature of SSN/DBO and why it needs to be defended. Also, clearly brings out the interlocked nature of defenses in the sector.
To information contained in the expedition report, let me add couple of points:
1. From Pratappur Sector at confluence of Nubra and Shyok rivers, road exists for sure till Shyok Village.
2.An alternate road now exists between Shyok Valley and Indus Valley. This one starts Agham in Shyok Valley, crosses over Wari La and meets the road which going towards Chang La ( but before Chang La).
3. Again, a road now exists between Tangtse, Darbuk and Shyok Village.
I'm attaching a crude map which shows the above routes. Hope it will be of help.
On the question of road to DBO from Shyok, BRO had started work on the same but reports say that the same is not complete. Having said that, if one were to examine the satellite image on Wikimapia or Google Earth, a road in many sections can be clearly made out. In fact, some kind soul has actually marked a road alignment as 'SSN ROAD' on Wikimapia.
Please check the link here:
In my opinion, some sort of road does exist from Shyok Village, along western bank of Shyok River and then entering the gorge towards Murgo (before the summer route from Saser-Brangsa to Chong-tash to Murgo).