They've got 3 harvesters running so this job should be done really fast - a week or two - so the trail should easily be all better by race day. They could be done with the trail J part in a day or two. The trail LL portion in the plantation could be done soon after that.
If you see the machines working, give them plenty of distance. Remember they are out there earning a living, and they are doing what they can to minimize their impact on the trail.