I stayed at the Hilton Garden Inn which is next to the Future of Flight facility. Odd numbered rooms would give you an airfield view, but not essential considering the lack of movements. Apart from a few Alaska E175s and GA it is only occasional Boeing test flights. Another reasonable hotel is the Best Western Navigator, with more food options nearby.
Much of the flight line can be viewed from the mound next to the Future of Flight, but a drive to the nooks and crannies is also needed, including the EMC facility, off 109 Street SW, where there are many KC-46s without markings! Nearby is another facility which always has a few Southwest 737s, while the excellent Flying Heritage Museum is in this area.
Credit: Steve Mitchell