Quickly...
A Challenger 604 at 30C and 4000 feet PA will require...
GTOW of 38,000 lbs = 5570' of Take-Off distance.
GTOW of 40,000 lbs = 6200" of Take-Off distance.
You can probably find a 604 with a BOW between 27,500 lbs (low) to 28000 lbs (high) which includes the 2 pilots.
Add 200 lbs for the third crew and 2400 lbs for the 12 pax and then add 8000 lbs of fuel for the flight and you fall easily between the GTOWs of 38,000 lbs and 40,000 lbs.
8000 lbs of fuel gives you the following… 1st hour = 3000 lbs, 2nd hour = 2500 lbs leaving you an extra 2500 lbs fuel. Two hours of flying time = more than 500 nm range.
Keep in mind those numbers are at 30C and a pressure altitude of 4000 feet with 8000 lbs of fuel so this should give you some good margins for operating out of your airport.
The newer 605 soon to be replaced by the 650 could be a bit lighter on their BOWs. You could also check on the Challenger 350 to see how it compares (I’m not familiar with it).