Tidy Cats “Small Spaces” litter smells absolutely awful, right out of the box.
A lot of motel rooms put the beds on wooden boards, so that it’s impossible to lose stuff under the bed (or, I guess, for ill-doers to hide there). But the wooden boards don’t always go all the way to the wall—sometimes they leave a little space between the wall and the board.

A lot of motel dressers have space behind or underneath the drawers, that can be accessed by sneaking up over the back wall of the drawers, and then down, or sometimes through the open back of the dresser. For humans to access it, you usually have to remove the drawer. Luckily, I haven’t found a dresser yet without removable drawers.

Cramming a pillow into these crevices might work, but an additional heavy weight on the pillow might be necessary.

Traumatized cats, once wrangled out from behind the bed/dresser and into a bathroom, just might then creep into their carrier of their own volition. Which is much easier than wrangling them into a carrier.