1) Trump does not need standard fundraising, although I think he WILL get substantial PAC money.
2) He is running an unorthodox campaign heavily media centered in this age of celebrity. Palin tried, but failed, to do this. He has managed to use the media against itself. He is using the new media to gain incredible face time before the public and even though he has negatives, overall he is doing better than Hillary.
3) Neither Palin nor he cared what critics said, but Trump, due to his ego, has managed to get sympathy and focus that hatred into a campaign positive. Maybe because of McCain, maybe because the time wasn't right.
The big difference is Palin believes what she says. I am not sure Trump does.