Travel to Hillhead Devon on Bank Holiday Weekend

Im travelling from Leeds down to Hillhead on 24.5.14.  Given it is bank holiday weekend i was thinking of leaving Leeds at 6am.   Can anyone advise me whether this is early enough to avoid the traffic jams or do i need to think of leaving even earlier?  Dont fancy being sat on the M5 for hours on end!!!

Also - is the best route M1/M42 and M5?

many thanks