When you were tracking him the 600 yrds did he happen to circle back around out was it a stright line away from you? And was there any pools of blood when you were tracking him.."like he bedded down or stopped and you bumped him" any sign of that??

But like said earlier, I would take the trail back up to where you last had blood, and take it slow, and look for the Crows or buzzards, but your in Vermont so its cold enough up there for the deer to be OK overnight..

Good LUCK!!