Furnace Creek to Panamint Route
The following is a 150 mile route:
1. Furnace Creek
2. Ubehebe Crater
3. Race Track
4. Double back to Teakettle Junction
5. Ride over Hunter Mountain
6. Connect to Saline Valley Road
7. Gas stop at Panamint Springs Resort
Based on your group and time of year, that looks like your best route.
With the two R1200GSA's I have ridden in Death Valley, I would usually get about 38-45 MPG based on this type of riding. It is all dependent on how hard you twist the throttle. I tend to ride in a more conservative manner.
I rode my GSA up Lippincott and just barely made it with TKC 80's installed. I dropped the air pressure to 20 psi but when you do that you have to be careful not to ride too aggressively. I hope he knows to disable his ABS when heading down hill on some of these dirt roads.
Riding from Ubehebe Crater to the Race Track will be a good test for your riders as there is loose gravel and rocks to contend with but it is level ground. There is also some silt to ride through as you head south on Hunter Mtn road which can also be a challenge but it is only about 100 yards long.
It is good you have a good size group so you can help each other if needed.d
You should have a great trip.
I came to ride...........