I routinely fly onto a strip which has steep slopes and intermediate bumps. A lot of what is posted above is not very helpful.
Too many baby airline pilots - PAPIS on a runway that really undulates????? Get real the diference in level here is certainly visible but it is not big enough to be an excuse for a poor landing - all of the variation will be within the ground effect zone, so if the aircraft is pitched up enough to keep the nosewheel clear you will see/feel very little difference.
Some of the other posters have the guist of it - looking at the end of my strip is not possible - it is out of sight! What is very important is looking at the touchdown point and making sure that the aircraft is pitched up sufficiently to ensure landing mainwheels first. The second action is to land using power. Most of the time I arrive with a fair level of sink, that added pitch increases the effect, the only way to land now is to apply power to control your height above the landing point.
This usually means increasing to power to 25% of so in the roundout to check the sink and then landing at idle. It does need a bit of practice but it is straightforward.
Landing without power requires extra speed, because of the added drag during the flare, and it makes the whole process less forgiving.
But as far as undulations are concerned, on the down part simply hold the attitude and do not let the sink rate build. If you attempt to alter the attitude of the aircraft to match the downslope disaster lurks there. The throttle is the answer.