I'm old and slow.
WIth that out of the way, the Mistlands is like the early days of the Swamp plus Mountain terrain. Starting from maxed Plains gear, it took a while to figure out how to operate. I found that the regular Seekers are very susceptible to elemental weapons. A couple of good combos with Frostner generally takes one or two out quickly. Takes me more maneuver to take care of the Soldiers. Frost and poison arrows and the poison effect from a maxed Draugr Fang are also effective.
I have now killed two of the Gjail--fire-breathing blimps. For the last one, I ran straight through the middle of a large Fuling village, with the blimp in "hot" pursuit. Had to circle around, knocking off groups of Fulings and shooting at the Gjail to keep it from retreating to the mist. It destroyed the village, shamans, and berserkers, and then I finished it with arrows.
I'm dying less than before, and Mistlands can sometimes even be sort of entertaining.