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