The Travelodge and Silver Cloud on 25th Ave NE are both decent and less than a mile from the start; Silver Cloud can be a bargain if you book well in advance, but can be hit or miss. Direct route or scenic route from Amtrak to Stadium?
Direct, Seattle Commuter Route - Right at first corner leaving station, right on S Washington, Right on 4th (can bear left on 3rd ave crossover if during rush hour, then 3rd has only buses and bikes on it through downtown), Right on Blanchard, left on 7th. 7th curves right and turns into Dexter Ave N at Denny Way. Continue N on Dexter up and over hill. On far side cross Fremont Bridge. Right on N 34th St (first right after bridge) Enter Burke-Gilman Trail at corner of 34th and Stone Way. B-G will take you all the way to stadium. 7.26 Miles. Here's a route map: King St to Husky Stadium/E1 Direct. (Map uses 3rd not 4th downtown)
More Scenic/Less Traffic Issues navigating downtown, less hill - Straight on King Street, right on Alaskan Way, continue along waterfront to Myrtle Edwards/Olympic Sculpture Park (where Alaskan Way curves right/ends at Broad Street), follow bike path north along water, past grain terminal, continue with trainyard on your right, exit/right onto 20th Avenue W, 20th becomes Gilman Avenue W, right on W Emerson Pl, immediate left on 23rd Ave W, left on W Commodore Way, follow to entrance to Locks. Walk bike through locks, enjoy the fish ladder. Outside of locks, right on NW 54 St, becomes NW Market St, right at 24th Ave NW, immediately bear left on Shilshole Ave NW, be careful of large trucks, after underpass, shilshole becomes NW 45 St, outside of Fred Meyer near intersection 11th Ave NW, Burke-Gilman Trail begins, follow all the way to stadium. 12.9 miles. Here's the link: King Street to Husky Stadium via Ballard Locks.
Not a hotel/motel, but CBC has had space in a dormitory at the UofW the night before the ride, in the past. Probably 1/2 mile to the start line. I live in the area, so haven't even considered it as an option/need, but it would be nice to just coast down to the start line area, toss bag on the truck, and roll out.