I have a senior pass for the park how much is the cost for the passengers

According to the USGS website the following applies: Allows pass owner and accompanying passengers in a single, private, non-commercial vehicle to enter Federally operated recreation sites across the country, Covers the pass owner and three (3) accompanying adults age 16 and older at sites where per person entrance fees are charged. No entry fee charged for children 15 and under

$80 Dollars for whole year, unlimited access to all US National Parks

When i visited the Grand Canyon it was with the Grand Canyon Bus Tours so i cannot be of help outside of telling you the experience was awesome. I loved every minute that i was there.