Sit tight, maybe someone else does have some experience, I am interested too. If I have my way about things this season, I will be taking both my kids to the MSF dirtbike school. I will take the course with them as a parent first and learner second (it's just the way I am). I will post up my impressions.
Now, take this with a grain of salt please. I have taught my son to ride a little bit. He is still very much a novice by my grading scale, which some say is very high
. But none the less...
I am super tired right now, but I might be able to help you with the gravel and sand riding. I have been riding over 1 solid mile of gravel to get home ever since they tared and chipped my road.
Until I get to posting, try this... Use your legs to assist the suspension to work as it should (there is more to that...). Ride light in the saddle and keep a loose grip like you have been but don't completely lose your lower body connection with the bike, the traction feedback is important, don't sit up on the tank, 40%/60% weight distro and for pete sakes... don't fight the front and have good throttle control. Gravel and sand is another area where smooth roll offs are as important as smooth roll ons.