...less load being the right answer is probably an even more appropriate solution when headed back down.
If you have to go that slow you're almost certainly overloaded.
True, don't have a weight for that trip, but it was close if not already overloaded.
The most memorable and miserable part was on I-64 in WV on
Sandstone Mountain headed home.
"It has some extremely rugged terrain, with one segment boasting a 7% grade downhill eastbound for seven miles (11 km) at Sandstone Mountain"
Grigg