Grade on US 89

Thanks paulj,Believe me I won't worry about going slow.This TV and TT combo is new to me,I really need more truck or less trailer,but I am within all specs but at the limit so just want to take advantage of any and all info I can get.I have been towing trailers of some type for most of my life,farm or otherwise.Being 78 years young This will most likely be my last trip that way,and being a flat lander and the amount we tow just dosen'warrant(sic) the expense of an over the road TV.Was trapped in Yellow Stone in the fires in 1988.