Protect face, hands and hootis...hootus? from the stuff. I wore a mask when I did the cab...also it will outgas for a couple days, give it time before you use it.
Thin is right. It's great for light duty and covering the floorboards but for heavy work try the spray-in. I have Rhino, LineX and Herc on my truck, all for completely different purposes, and they work great as long as you ask the right service from each coating.
Herc is GREAT to stand on. Rhino is good for standing, sitting, kneeling, and more gentle with your stuff (Herc and LineX are more abrasive). LineX can't be beat for sheer durability but it's not comfortable to move around on, slippery, and hard on nice stuff like bikes etc...I have Herc in the cab, Rhino on the roof/front bumper/bedrails, and LineX in the bed. Works out great.
-Sean