http://www.baseops.net/c130pilotgouge.html

You can look on here, this is real world C-130 information that can be used as reference for the virtual world.   C-130's are usally kept below FL300 for other traffic that may be faster to travel.   The J model can get up higher but FAA may keep them lower due to airspeed.

Typically in the vUSAF we keep the C-130s anywhere from 500 AGl to FL290/280.  

The standard rule defines an East/West track split:
Eastbound – Magnetic Track 000 to 179° – odd thousands (FL 250, 270, etc.)
Westbound – Magnetic Track 180 to 359° – even thousands (FL 260, 280, etc.)

At FL 290 and above, if Reduced Vertical Separation Minima are not in use, 4,000 ft intervals are used to separate same-direction aircraft (instead of 2,000 ft intervals below FL 290), and only odd flight levels are assigned, depending on the direction of flight:
Eastbound – Magnetic Track 000 to 179° – odd flight levels (FL 290, 330, 370, etc.)
Westbound – Magnetic Track 180 to 359° – odd flight levels (FL 310, 350, 390, etc.)


Ceiling:
C-130J: 28,000 feet (8,615 meters) with 42,000 pounds (19,090 kilograms) payload
C-130J-30: 26,000 feet (8,000 meters) with 44,500 pounds (20,227 kilograms) payload.
C-130H: 23,000 feet (7,077 meters) with 42,000 pounds (19,090 kilograms) payload.
C-130E: 19,000 feet (5,846 meters) with 42,000 pounds (19,090 kilograms) payload

Don