You don't want to be right on the front just near the front, if somehow you do end up there you won't be there for long anyway as the bunch will come past if your slow on hills.
Also don't go using up energy to get up near the front just before the hill, use any opportunity to gain bunch position without using any energy, if the bunch slows don't put brakes on and slow down, roll around the riders and get bunch position in large bunches in opens this tactic can save you a lot of energy.