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

Figure the C-130 base climb rate at 1500fpm and based 250 knots below 10,000 it will take the C-130 about 6 minutes to climb to 10,000 from example Little Rock AFB which is 371 feet MSL.

Remember what type of flight are you flying as well, IFR or VFR as you could fly the 100nm at 500 AGL or up to FL180.  Climb rate, distance and airspeed play part of altidue along with weight

Example I pulled up was a turbo prop, KLRF to KMEM which is 107nm estimated time 0.29 mins, altitude 18,000 average heading 285 average windspeed24 with airspeed 250

http://airplanemanager.com/flightcalculator.aspx