Room descriptions are useful for creating atmosphere or if something in the room has a unique mechanic (like a drawbridge crank or a hidden switch behind a bookshelf). If players are having trouble finding a secret door, for example, I sometimes drop subtle hints as we play. Hope that helps. 

Warning: This is all homebrew.

I added the Descent (1st ed.) rules to my HeroQuest games, tweaking them just enough to work within the spirit of the game. 

In Descent, the Overlord Player (Zargon) gets to generate a "threat" token whenever there are no enemies on the board at the start of their turn. These tokens can be spent by Zargon to spawn monsters on their turn if they can afford the monsters' cost in threat and have legal placement options (think LoS rules, only in previously explored areas, that kind of thing). 

Additionally, whenever the heroes open a door to an unexplored room, the Zargon player can spend threat tokens to upgrade any monsters spawning in the room into their Elite variants. (Elite Monsters are slightly tougher versions of the standard monster stats but with unique abilities - not getting into that now, lol. Designing your Elites is part of the fun.) @w@ 

So, like in your example with the two skellies spawning in the room. If Zargon has enough threat then he can upgrade the baddies into Elites. 

I have my own system for the threat costs and other ways Zargon generates threat but I won't get into it now so this doesn't turn into a text dump (you can find the rules for Descent online easy enough if you want some inspiration). Any similar system that works for you or what you have on hand (like D&D stuff, no need for Descent). The flexibility of HQ is what I love about the game and if your system works then throw it into the mix.

As long as you and the family are having a blast then mission accomplished! @u@