I think i know the answer but would like to hear others opinion . I'm in west yellowstone on Hebgen lake . a large body of water about 9 miles long and a mile or 2 wide . 80% of the lake is open air space class g . it is surrounded by mountains that average about 800' to 1100' above lake level . so now the question since i start at the lake lets says that 0 elevation and want fly to the top of the peak at 1000' basically following terrain up . i need to set my max elevation at about 340 to 350 meters . this of course is way over the max flight altitude of 400' . All though at no time will i be more then 150' elevation AGL during the flight . but will be 1000'up from my starting point . what say you all in compliance with FAA rules in part 107 or not