It's pretty easy to get 1st place on all the races especially once you learn the shortcuts. Some of the Easter eggs are placed in spots that are shortcuts like the one on The Ruins is really good and Firewater as well.
Also as DugFreez pointed out in the comment below: you can go into the options and set the difficulty to Easy.
If your having trouble you can check out my Achievement Review/Tips Video:
There's tips throughout the video but
I go over how to beat Krex at 4:50
I go over tips for the freestyle events at 7:15
I show where all the Easter eggs are at 13:55
*Correction* For beating Krex I used the Scorpion but thats actually the hydrojet you get from beating him so you should use the Striker or Shockwave