Okay that's good.
When you say rooms do you mean these can only be done in multiplayer? I haven't touched that yet so I don't really understand it too well. Was just planning to go solo until it became impossible.
Depending on the monster I would not recommend some deviants solo. The level 1 Dreadking Rathalos was my first timeout - although I went in somewhat unprepared, wrong kind of earplugs, no cats, missed a trap and didn't understand how to flashbomb him. I feel confident that I could easily solo others like Crystalbeard Uragaan to 10, if I had the time or inclination.
In particular you're looking at 20-30 monster clears for the armor set, and minimum 10 for a weapon. I only
had to do 10 Grimclaw Tigrexes for my hammer (did 5 or so extras to help out) and that was a significant time investment. I'm not afraid to solo anything in this game but I don't have the patience to farm that long, so multiplayer is convenient.
You can enter random rooms specifically for that monster or join one of our GAF rooms and take turns. I've got Dreadking up to 7 by doing the latter and I've helped others plenty.
edit: to be clear, deviants are grindy but optional. There are weapons and armor on par with their stuff from Hyper monsters, and those don't really take more than the usual number of clears. I use the Grimclaw Tigrex hammer but many use the regular Tigrex hammer over it. I just like the faster Arts building and think it looks cool. And I've liked fighting most of the deviant monsters so far, even if Rathalos is a gigantic jackass.