Underhill to the Hive isn't that easy, for Barnet FC games the club lays on shuttle buses. There are a couple of buses, 107 from Barnet or get the tube to Whetstone and the 251 bus to Edgware.
Easiest option is probably get the tube into town and change to get the tube to Edgware or Canons Park but that's 1 1/2hrs.
However you do it, if you're not driving then it's at least an hour and probably nearer an 1 1/2hrs.
Going on a journey planner website the best I could find for this Sat is :
Barnet, Barnet Church Wood Street, Stop E
Take 13:52 Bus 107 towards Edgware Station and get off at Borehamwood, Stirling Corner, Stop A (on Barnet Lane)
Take Bus 292 towards Colindale, Colindale Asda and get off at Edgware, Whitchurch Lane (S-Bound) (on EDGWARE HIGH STREET)
Then walk for about 19 mins to the centre of Canons Park arrive 14:57.
If you stay on the 107 then you get to the Hive at 15:03.