I am assuming you have the bed set piece on a castered platform.

If so, there is a piece of door hardware that screws to the bottom of the door.  This door stop has a slide with rubber at the bottom.  You step on the slide, down it goes to the floor, and it clicks into place.  The only time we don't use this hardware is when we require absolute silence during a change, but we often change with some music, so it's usually not an issue. This totally eliminated our need for locking casters.  Now we only buy fixed or rotating as needed. Benefit: You can lock your plat anywhere. Downside: You still have to hit your spike marks

If you can drill into the floor, consider using two pegs on the upstage side to keep your platform from moving.  Benefit: You always lock your platform in its spiked position.  Downsides: Many of us can't drill into our stage floors...after a time your pin hole tends to get bigger and your plat will drift....harder to hit your spike because your aiming for a specific point in space rather than a general area.

Another thing we've done is to use furniture slides.  These metal or plastic units are designed to be hammered into the bottoms of sofa, chair or table legs so as to not scratch hardwood floors.  When the platform was fairly light and we had a large enough crew, we'd use eight or ten of those buggers tacked to the bottom of the platform. Benefit : Much cheaper than casters  Downside:  Needs more labor to shift the scene.

Definitely use stage brakes. They are cheap, last forever, and do what they are supposed to. They are also a whole lot easier to lock and release during scene changes.