Easy, pardner. That's the first thing I think whenever I see a new book that has anything to do with Montana written by somebody who doesn't live here, as I do. The Lewis and Clark Expedition has something to do with Montana, more than tangentially. But it still piques my sense of Montana chauvinism when some Eastern dude, in the original sense of the word, comes cantering up with his shiny new spurs a-jinglin' and janglin' and announces he aims to write a book about it.

Defensible or not, I have my persnickety opinions as to who may and may not write about Montana, and rare is the book that can charm me as quickly as did The True Account. Quickly, though not immediately. The character of Private True Teague Kinneson, who springs to life virtually fully formed less than 15 pages into the novel, at first seems a little too perfect. A little too eccentric-Yankee-uncle perfect, to be precise -- which is exactly what the private is to his nephew, Ticonderoga, the admiring acolyte charged with both keeping an eye on the private and penning this fanciful account of the race, led by his uncle, to the Pacific across the Louisiana Purchase.

Private True Teague Kinneson has what the soldiers of Erich Maria Remarque's All Quiet on the Western Front referred to as a "shooting license" -- a head injury that absolves him of responsibility for his actions. He received a sharp blow to the head shortly after the battle for his nephew's namesake fort on Lake Champlain during the Revolution, and ever since he's been a couple tampings short of a musket load.

True Teague Kinneson is a combination of holy fool, mad inventor and deranged demagogue who takes vigorous intellectual issue with everything from Hamiltonian Federalism to Linnaean taxonomy. He wears a codpiece (incorrectly), a stocking cap with bell attached (so he always knows where he is), and a copper dome to hold his noggin together. He's also an early pothead, but instead of sitting around staring at backlit woodcuts, True prefers to spend his THC time mounting classical voyages of discovery in miniature in his backyard.

All in all, he's a more suitable candidate for tilting at windmills than manfully divesting virgin territory. That, however, is the last of the reservations I harbored before finding myself dragged along on the private's transcontinental quest as imagined in Mosher's novel-length shaggy-dog tale. A Montana picaresque with a Yankee crackpot reprising the role of Don Quixote? Why not?

When the private goes missing from his Vermont home, Ticonderoga tracks him to Boston, where he is mustering a cast of street urchins for one of his beloved illumination plays -- in this case, the spirited defense of Bunker Hill reenacted with snowballs. Ticonderoga learns that his uncle's fugue is actually a self-styled fundraising tour to raise a stake for a "second" transcontinental voyage of discovery -- the "first" having been one of the private's many backyard odysseys with his nephew.

Their quest eventually leads them to Monticello, where a bemused Thomas Jefferson informs them that an expedition has already been organized with two now-famous captains named as its leaders. Kinneson is disappointed but typically undaunted. Ticonderoga's plan, suggested by Jefferson, to lead his uncle back to Vermont while pretending to strike out westward, quickly goes awry. Uncle True might be a fool, but he's no dummy.

So off they go, westward ho, sometimes neck-and-neck with Lewis and Clark and more than once saving the Corps of Discovery's bacon from hostile Sioux and a roving Spanish "force of terror," among other undocumented threats. Along the way, they also meet up with an assortment of stalwart native chieftains and comely maidens as well as real historical characters such as Daniel Boone and John Ledyard, nearly, but never quite, managing to get themselves written into the official annals of frontier history.

Until now, that is. Close readers of Mosher's novel who also happen to be Montana history buffs will notice a number of incidents transposed from life. The story of John Colter, for example, who outraced a party of several hundred Blackfeet warriors barefoot and ran stark naked across six miles of cactus-stippled prairie, appears not once but twice in The True Account.

My history-majoritis flared up a couple times at anachronisms both historical and linguistic. Mosher does a pretty good job of sustaining a period voice in his narrative, but slips up here and there -- though rarely for longer than it took me to jot a note in the margin. It's hard to stay mad at a book as guileless as its addle-pated hero, True Teague Kinneson. If and when Vermont filmmaker Jay Craven gets around to making The True Account into a movie, however, there surely will be a role for Tantoo Cardinal.