IMO, we have to remember that he'd spent a long time prior to the escape in prisons and jails. Maybe an actual bed, an actual room, a TV not shared in some inmate recreation room, eating what he wanted when he wanted it, no all night shouting from prisoners nearby, whatever---maybe it felt luxurious.
They certainly had the money to stay in a cleaner and much nicer place, but that would likely be more high profile, more subject to careful check on who they were, more scrutiny all around.
Someone pages or threads ago also alluded to the homeless guy who did the check-in as a culpable third party who got his punishment by "having" to stay in this hotel for five extra days after CW and VW went on their last ride.
I think it's important that we don't put our own perspective of comfort on people who slept on the streets or in a jail cell prior to this (admittedly shabby) motel.
Unless Vicky wrote a journal, or left letters for her family or something, the only explanation we will ever get is from a deranged, violent criminal whose self-interest will be paramount in his version of the story.
All that's left is the unanswerable, and the grief I feel for her sorrowing, hurt and bewildered family.
JMO