What type of fishing license should I get?

Let's look at the economics of the various license options.  You could buy a Nonresident Fishing license ($98.25) and a Nonresident Steelhead permit ($25.75) and fish all year for steelhead in Idaho.  It would also give you the latitude to return in the fall and fish for steelhead at no additional cost.  You could also fish for salmon in the spring or fall with an additional nonresident Salmon permit for $25.75. If you want to buy 3-Day Salmon/Steelhead permits (includes a 3-day nonresident fishing license) they cost $25.75.  You would need to purchase 3 individual permits for a total of $77.25 to fish for 7 days.  If you go this "route," you might as well plan on a 9 day vacation rather than 7 days.