9g
has a good point...if you are on airways, and the MEA is FL180, you are ok...but stay on published route.
also, if in RADAR contact you could ask what the minimum vectoring altitude is, and if below driftdown alt, request vectors to lower terrain.
there might be ONE controlling obstacle in the grid, requring the higher grid MORA (like one mountain peak at 20,000feet) and you might be fine...
BUT, I always carried VFR charts to supplement IFR charts...to find that one peak.
WHERE are you ? Tibet?