I converted my SRAM Force road bike to mountain gearing by installing a SRAM Red 11-32 10-Speed cassette and a SRAM XX Mountain rear derailluer.
It all works well with my standard SRAM Force shifters, but pls. be advised that there is no cable tension adjustment on the mountain rear derailluer (this function is covered by the mountain shifters in that context). Plus the XX takes a torx wrench on the cable clamp bolt (not the usual 5mm Allen).
For cable adjustment I retained my Shimano devices on the sides of the downtube (where down-tube shifters used to be). And it works, but just keep that in mind if you don't have another rear derail. cable adjust option.
Rick / OCRR