1) You get the Runed Totem Staff off of Rex, the gnoll shaman, in Split
Paw, more commonly known as Paw.
2) I am not sure about where you get them but as far as I have heard no
one knows how to mount them anyway.
3) Yes there are plenty of magic rings out there. You can either find
them off of certain creatures or get a high level enchanter to make them for
you.
4) Don't worry about cooking, you can eat the fish that you catch
without doing anything to them. However, if you sell them fish for 2 Silver
3 Copper, or whatever you get for them, you can almost afford to buy 1 food
and 1 water for the same price so it is more economical to sell them.

Yours,

~Aereuss Ravins of Tarew Marr