Another 1 has run it.  It is NOT the toughest race by a long shot.  It is a challenge, but not too bad.  Their elevation metrics are a total lie since they use uncorrected GPS elevation data for their course (which always way overestimates elevation change) when comparing with elevation data for other marathons. 

Here is what they say:

• Yukon River Trail Marathon (Canada’s toughest) 8000’ elevation gain
• Pikes Peak Marathon (Colorado’s toughest) 7815’ elevation gain <- actually, about 10 000; this only measures the bottom to the top and none of the rolling
• Indian/Celina Challenge (Indiana’s toughest) 6300’ elevation gain <- probably more like 3000-4000.
• Saddleback Mtn. Marathon (California’s toughest) 5100’ elevation gain
• Tecumseh Trail Marathon (near Bloomington, IN) 3500' elevation gain
• Grandfather Mtn. Marathon (West Virginia’s toughest) 3000’ elevation gain <- road marathon; cannot compare
• Land Between the Lakes Trail Marathon (KY) 1100' elevation gain
• Boston Marathon (World Renown) 459’ elevation gain

Apparently the trail is not very technical, so this might be a good first trail marathon.  I may run it some day, but it has conflicted with travel last year and this year.