I like this plan. Every thing looks easy to work with. You’ll be able to turn the horses out into the dry lot. Then gates to pastures 2, 3 and 4 make that “auto” turn out.
Looks like the barn will have easy access, the MIL parking spot is really close and there is no “yard” indicated in that area so I’d assume it will be driveway.
Also it looks like only the far pasture is next to the main road. So that should minimize people stopping. No matter where you put the pastures people are going to be able to see your horses from the road.
That said, not only can people hurt your horses but there is the “attractive nuisance” issue. Stupid law: A dangerous condition on a landowner’s property that may attract children onto the land and may involve risk or harm to their safety. Because child trespassers may not appreciate the risks that the dangerous condition poses, landowners have the duty to either eliminate that danger or make it inaccessible to trespassing children. I’ve read articles where parents have sued because the child went into a pasture and was “bitten” trying to feed an apple to a horse.
All horse owners need to have a blanket farm policy to protect them when some ridiculous parent sues you because their kid crawls under your fence to pet your 1,200 lb horse.
In my area I have to post no trespassing signs fairly close together and at all possible entrances, so that I’m not liable if a kid (or adult) gets hurt when they trespass and ride there ATVs in my crop fields! Problem - said kids regularly rip the signs down. Other problem, father puts his hunting stand in the middle of my woods - and chains it there! Fortunately that’s what bolt cutters are for.
And don’t forget to post the “hazard/danger electric fence” signs. 