You can take a taxi or Uber/Lyft from the airport and will cost you between $40-$80 depending on time. Make sure to check the taxis as they are often a flat rate of $40-50 to get you anywhere in downtown Seattle from the airport.

If you do not want to rent a car or use ride share, you can take the Light Link train directly from the airport station to the Symphony Station. Total cost for that is $3.00 each way. From there, you have about an 11 min walk to the Renaissance Seattle Hotel. The walk does include hills as this is Seattle and walking almost anywhere includes hills.