Trying to find a book I read probably in the early 80s, about 2 brothers who were shipwrecked on earth, and lived among mortal earthpeople for generations; the wrecked spaceship was someplace in Maine or Vermont and in "modern" times the place was considered haunted because the ship's AI sometimes roamed around. One of the brothers killed the other brother's wife and they then spent thousands of years hunting each other; one brother ends up in a US prison from Civil War time and manages to escape while being transported thru NY City. At the end the disabled space ship is reactivated and starts to destroy the earth, which the "good" brother has been trying to prevent...and it turns out the wife was murdered by the AI because it didn't want the brothers to settle down but to complete their mission of destruction... Ring any bells? I've been looking for this for years, any help is appreciated!
My mind keeps circling back to Keith Laumer, but I know it's not The House in November... Could it be The Long Twilight (1969) by Keith Laumer?
For hundreds of years, Grayle and Falconer have battled across Earth. Their conflict has created myth (Falconer is also knows as Loki, Grayle as Thor) but has been largely personal until now. With the perfecting of broadcast power, Falconer finally has the power to accomplish the mission he set off to do thousands of years before--although it means the destruction of the earth. When Grayle feels the renewal of his energies, he knows that the time has come for the final conflict--not between good and evil, but between life and destruction. Already an inexplicable hurricane rages in the Atlantic--a storm that will continue to grow unless Grayle can discover some means of stopping it.
Aided by the power of their ship, the two men are essentially supermen, yet they have the same moral and mental limits of any human. Grayle is a traitor to his cause, setting the lives of millions on Earth ahead of his duty to his warring people. Falconer knows that the greater cause may require sacrifices, even horrible sacrifices, but failing to do so will result in even more serious destruction. And they are not alone. Now tht it is powered, their ship can play an active role and spoil all of their plans.
The Long Dark Tea Time of the Soul is about a space traveler marooned on the Earth near its birth; billions and billions of years ago. The spirit of this traveler is in fact responsible for life on Earth. He waited all this time to for 'life' to create a time machine so he could go back and change the mistake that marooned him here... but if he does? Poof. And there is a bunch about a ghostly software magnate, his sister, her boyfriend, an aging professor, our man Dirk Gently, and a couch that disobeys the primary laws of physics but the important part is the long lived space traveler's spirit.