This secrecy disturbs Patrick Garren, 38, a business owner here who belongs to a laid-back evangelical church favored by the Harley crowd.
"Why am I not cleared to go into your church? What is there to hide?" Garren says.
"I won't vote for Mitt Romney, because of his faith. I don't approve of the way they conduct business."
His pastor, Tim Fowler, in jeans and black T-shirt, listens sympathetically but can't quite agree. "Am I concerned about his faith? Yes. But would it stop me from voting for him? No," says Fowler, 46. Before he makes a decision, he explains, he'll want to learn more about Romney's policies.
Those policies appeal to many evangelicals, especially in the conservative South. Romney has switched views on several key issues, but the strong stances he now takes against abortion and same-sex marriage resonate with voters here. His lifestyle, too, wins wide approval. In accordance with Mormon doctrine, Romney does not smoke or drink alcohol -- or even coffee -- and he gives 10% of his income to the church. He has been married to his high school sweetheart for 38 years.
That all sounds good to Rhonda Johns, who has just spent an evening at Trinity Bible Church, watching teenage girls in white gowns pledge chastity until marriage.
"Morally, there are a lot of things we have in common," says Johns, 55.
There are, however, a few subtle distinctions.
Many evangelicals consider abortion -- in any circumstance -- murder. Mormons do not. The Mormon Church teaches that our spirits are alive long before we are conceived; the theology is vague on exactly when those spirits enter the fetus in the womb. Perhaps because of that flexibility, the church permits abortion in cases of rape or incest, if the mother's health is at risk, or if the fetus has severe deformities.
After years as an abortion-rights supporter, Romney now opposes abortion and says he would like to protect life from conception onward. But he has declined to call abortion murder -- a hesitation that one of his opponents has tried to exploit. Kansas Sen. Sam Brownback, who is Roman Catholic but has strong ties to evangelicals, sent out a news release this month with the heading: "Mitt Romney Doesn't Believe Abortion Is Murder."
Romney -- who is leading in early polls in Iowa and New Hampshire -- has also faced more direct attacks on his faith. An anonymous eight-page screed against Mormons was mailed to some South Carolina residents before a Republican debate last month.
A Florida pastor named Bill Keller recently sent out a mass e-mail comparing Romney to Satan and proclaiming that Mormons would "spend eternity in hell."
Still, Romney has not conceded the evangelical vote. He invited leading pastors to his home for dinner last fall and gave the commencement address at Pat Robertson's Regent University in May. This courtship has paid off with public statements from leading evangelicals who have pledged to give Romney a fair hearing.
"The Mormon faith -- most Christians would consider it a cult," says Franklin Graham, who runs an evangelical association named for his father, Billy Graham.
"But I've met Mitt Romney. He's a very nice man. Very brilliant. And he's a conservative.... In certain circumstances, I could vote for him."
Many here agree with that assessment: In the general election, they'd much prefer a conservative Mormon to a liberal of any faith. Democrats Bill Clinton and Jimmy Carter are both born-again evangelicals -- but conservatives widely consider their presidencies disasters.
"I have no problem voting for a candidate who disagrees with me on theology. I do have a problem voting for a candidate who disagrees with me on moral values," says James, the pastor's wife. The women of her Bible study nod. "I think we would all say 'Amen' to that," says Trudy Laub, 69.
But to reach the general election, Romney first has to win in the primaries, when Republican voters uneasy about his faith can choose another conservative.
Several women in the Bible study favor former Arkansas Gov. Mike Huckabee, a Baptist minister. They're also eager to hear more from former Tennessee Sen. Fred Thompson.
Back at the bookstore, assistant manager Thurman puts it this way:
"If the candidates line up on policy, you go to the next line. If one's a Christian and one's Mitt Romney? I have a feeling I'd vote for the Christian."