1994 Dodge Intrepid Flywheel

My car stalls when I wait at the traffic light. The engine clicks and then stops. When the gear is in Park the engine runs ok but when the gear is in Drive or Reverse the engine stops after clicking.
I showed it to a mechanic and he diagnosed the problem with flywheel. Cost of replacing flywheel $100 for parts and $500 for labor (6 hours) = $650 estimate with tax.

1. Does it really take 6 hours of labor to replace flywheel? $650 is a lot of money especially when the price of car is a total of $1000 kbb value.
2. Should I ask the mechanic to check/replace the timing belt (or does it have a chain?) To save on the labor again? Or since the car has 114,000 miles, it is too early for that?