The Milepost is updated annually and covers just about every single possible route to get to Alaska and to get back.
The Alaskan Camping book is often mentioned in the same sentence with The Milepost. It's been interesting but not as much help - it talks a lot about RV parks with full hookups and not so much about little niches with space for a single unit desiring to dry camp near a creek like we prefer.
Marianne Edwards' A Frugal Shunpiker's Guide for the Sierra Nevada Mountains has impacted our trip planning. Because of her book, we'll spend nearly a week wandering through the California gold country, checking out buildings and museums related to the California gold rush before jogging over to the coast for some of the Oregon lighthouses. Our first reservations are for the Northern Oregon Gathering (NOG) - a meeting of fiberglass trailer owners held this spring at Champoeg State Park near Newberg. After the NOG, we'll spend time with family in Olympia, fix windows at Glory Farm, and spend a few days with Mom before continuing further north.