On the blue stuff, just read the directions on the side and cut the amount it half
Yes the toliet uses the pump. Not sure what you have but all have some way to just add water to the bowl (for serious duty) or a normal flush.
I think a little water in the bottom of the black tank is a good thing. We typically throw in some detergent as well.
There are a lot of good camping spots near Cincinnati. Whitewater in Liberty Indiana is a good place to go if you want to get away. It is about 45 minutes from Cincy.