First, despite the fact that in some states people have organized an independent party under its name, the "Tea Party" as a whole is not a political party. It is a political and ideological movement that is pushing for politicians to represent their ideals...be it on the republican ticket, libertarian, conservative, etc.
Second, because of this what you're going to find is something similar to other political movements rather than parties...that you have people who support it and rally behind it that agree on the common interests of that movement but disagree on others. Much like the Anti-War movement could attract people who were pro-choice but anti-gun control or pro-life but pro-environmentalism or whatever else odd mix. That didn't mean the Anti-war movement was a Pro-Choice movement or an Anti-Gun movement, it just meant it had cross over.
The Tea Party's philosophy advocates fiscal conservatism, limited government, and an attempt to returning to more strict following of the constitution. It is not a social movement. However, its tenets DO appeal to many Social Conservatives and the Religious Right and even some Neocons or even Democrats. So they grab onto the Tea Party for the things they share in common, but that doesn't silence them about the things that they feel that aren't part of the core ideology of the movement.
Additionally, it is not a purely concentrated national effort but more of a loose confederation of multiple individual groups floating freely under a larger net. A Tea Party in Vermont may be organized and ran by a staunch libertarian while one in Texas could be ran by a Religious Right minister while still another two in Virginia could be within 100 miles of each other and one started by a moderate Republican and the other by a rather paleocon whose a hidden racist. In each case you'll likely find an underlining similar message...limited government, fiscal responsibility, a return to the constitution...but beyond that each will be shaped a bit by the person organizing it. Rather than look at the exceptions to the rule at each place I would say to get the real essence of the Tea Party movement would be to look at the message that is consistent through them all.
That in part is what the Contract From America is. Its backed and pushed by a coalition of various state tea parties and organizations that agree with and foster the movements ideals. It is that baseline message, the core of the philosophy.
And, sadly, like any group that gains large traction and gets a large voice you're ALWAYS going to have people that clamor onto it in hopes of using it and manipulating it without any real care for its meaning and message. Ultimately, for me, the Tea Party is not about any individual politician...certainly not Sarah Palin...but about a movement that is telling Republicans across the board that they had best start running as balanced conservatives focusing on fiscal and governmental matters and that when they're re-elected they best back up that talk.
The Republican Party has supporters and hangers on that are crazy idiots. The Libetarian Party does. The Constitutionalists do. Neoconservatism does. Paleoconservatism does. Libertarian conservatism does. Conservatism as a whole does. As does liberalism. And just about any political group, party, or ideology.
I generally don't judge a political entity solely on the basis of the crazies, even if that's what I've met first hand, unless there's overwhelming evidence that the crazies are the majority. You have, if nothing else, first hand accounts from numerous DP members...from right wingers that people can't stand to right wingers that others on the right call "phonies"...telling you they've gone to these things and the crazies were in the absolute minority. At the very least that should give pause to the notion that everywhere somehow its always the crazies in the majority.