According the the book I have there are 2 piers in Seattle--66 and 48; the latter being the State Ferry terminal.
And, according to another book with hotels: Pier 66, between Pike and Bell St the hotels listed that I can locate are the following:
Mayflower Park, Warwick, Clearmont, West Coast Vance*, Paramont*, and Roosevelt*. Of these, 3* can be reached through an 800 # of West coast Hotels 800 426 0670
We have never stayed at any of these so no help there. We have seen the Inn at the Market on Pine St (near Pier 66), but that is as close we got. I know friends who stayed there and found it OK. We did stay at the Westin for 2 nights and it was within walking distance of the * hotels.
No place I have mentioned is particularly cost effective, but I doubt anywhere in Seattle close to your destination would be. Or, if it was under $100 a night you would not want to stay there.
Had you thought of an airport hotel with downtown transportation? I think the Best Western has this option.
We have been to Tanzania, not on a specific photo safari, but that is all we did--take pictures. Yes, the trip home is a killer. I figure I had supper with wine at some ungodly hour not resembling any mealtime at home and then lunch with wine at what I felt was probably breakfast at home. It took weeks to recuperate, but I would not give up the experience for anything. A truly exotic adventure!!