Crackerjack (1994)

It's Die Hard...
in a mountain resort, which makes it Die Hard meets Cliffhanger

Is the main character an average Joe?
He's a cop named Jack, hence the title, played by Thomas Ian Griffith.

Sidekick?
Nastassja Kinski turns out to be a resourceful hotel worker

Any personal problems?
His wife and daughter have been killed by the same guy who is now trying to steal a valuable object from the resort. What are the odds right?

Is the lead character there by coincidence?
He's on vacation, so yes.

Are there any friends or family in danger?
Just the people at the resort.

What's at stake and why aren't the authorities doing anything?
The villains are trying to steal 50 million in diamonds. The lives of everybody in the resort is at risk. You don't have police near isolated mountain resorts usually so the authorities can't get there really fast.

Any charismatic villains?
Christopher Plummer tries his best to do a Eurotrash villain.

Is it any good?
No but it did get two sequels in which the second also had sort of a Die Hard plot and starred Judge Reinhold. They all have different characters and actors playing them. The second one was also released as "Hostage Train" so it's quite a confusing "franchise". Doesn't matter, only a handful of people have seen these films.