You may be wondering if there’s a difference between a spoonful of sugar or a spoon full of sugar. The same applies to roomful, forkful, and numerous other words. And the answer is yes!
A roomful of people is a measurement, albeit an imprecise one. It’s how many people it takes to fill a room (hence the imprecise nature–it could vary based upon the room). But still, it’s a number of people. When referring to spoonfuls, forkfuls, stadiumfuls, boatfuls, etc., the same applies. It’s the amount or number required to fill the container.
A room full of people, on the other hand, is literally a room that is full of people. The same applies to a spoon full of sugar, a fork that is full of pasta, etc.
While the meanings of the two phrases are similar, they are also subtly different and worth considering as you edit.
As always, feel free to ask me if you have any questions, and I hope this helps.