This summary is written west to east, but I’ll be riding east to west. I took this from the adventure cycling website:
A CLASSIC ROUTE AS OLD AS BIKECENTENNIAL Grand parks along the TransAm include Yellowstone and Grand Teton National Parks, among the best in the United States. One additional treat: because this route has been ridden by cyclists for years, many of the cafes, restaurants, and overnight accommodations along the route have kept journals consisting of entries written by cross-country riders from previous years, providing you with a cyclist’s history of the route. Plan on around three months (give or take) for the crossing. Some traverse the route quicker, but this leaves less time for sightseeing. This route can be ridden from May through September. Note that snow can occur at any time in the Rocky Mountains, and the highest pass on the route is over 11,500 feet. Although the prevailing weather patterns are from west to east, local wind patterns are more dependent on the passing pressure systems and local terrain, so you can expect your fair share of tailwinds and headwinds regardless of which direction you ride the route.
Astoria, Oregon, with the hills of a miniature San Francisco, is the official beginning-of-the-road. The view from atop the Astoria Column is well worth the uphill pedal. Stretches of beaches, outstanding state parks, steep ascents and descents, and great seafood abound during your first days of riding before you turn inland to the Willamette River Valley. Eugene is the largest city along the route, with about 140,000 residents. Other sizable cities along the way are Missoula, Montana; Pueblo, Colorado; and Carbondale, Illinois. The lush, green western side of the Cascade Mountains is a startling contrast to the dry terrain you’ll be riding into after McKenzie Pass. The road over McKenzie Pass literally cuts through an ancient lava field and offers spectacular views of the Three Sisters and other snow-capped volcanic peaks of the Cascades. Central and eastern Oregon is made up of dry, mountainous terrain and is good place to carry extra water. The National Historic Oregon Trail Interpretive Center outside of Baker City is a must-see, and after completing your trip crossing the country, you’ll have no trouble relating to the experiences of the early pioneers.
Idaho offers a wonderful ride along the Salmon River, and some interesting Native American historic sites to visit. The route then follows the winding, scenic Lochsa River for the longest ascent of the trip (around 70 miles). You’ll climb up and over Lolo Pass, enter Montana, and soon reach the spur into Missoula. Missoula, a college town, provides one of the highlights of the route, featuring Adventure Cycling headquarters with its “cyclist’s lounge” and other amenities, along with whatever services you may require in town. Beautiful panoramas and mountain passes await you in Montana.
The views in Yellowstone National Park and of the Grand Tetons in Wyoming are incomparable, and memories will last a lifetime. It’s worth an extra day or two off the bike to experience as much as you can of these two phenomenal national parks. Towns such as Dubois and Lander remind you that you’re in the West, with their historic architecture and western-style cooking. Lamont is an oasis in the windy, desolate Great Divide Basin, and serves up a mean bowl of chili.
The scenery quickly changes from dry, high desert to alpine as you reach Kremmling, Colorado. Touristy Breckenridge is another great place for a layover day. You begin a long climb to crest the Continental Divide at Hoosier Pass, 11,542 feet, up amongst snow-covered peaks. As the route leaves the Rockies, Royal Gorge Park offers a fun layover day, either for hanging out at the Arkansas River bridge or taking a helicopter ride over or a raft trip through the gorge. Pueblo offers bike shops and great places to eat; it also serves as the halfway point of the TransAm Trail (time to celebrate!). It’s a good place to stock up — it’s the largest city you’ll pass through until Carbondale, Illinois.
Things start to dry out as you get into the eastern part of Colorado and cross into western Kansas. Carrying extra water is a good idea here — this is hot, barren country. Right around Haswell, Colorado, you’ll see your last hazy glimpse of the Rocky Mountains. Overnights at city parks in Kansas are usually accompanied by cool dips in the city swimming pools. You might have to do some early morning and early evening riding to escape the midday heat. Don’t miss the pies at Cookie’s in Golden City, Missouri! The flat-as-a-pool-table terrain of the Great Plains will change quickly into the roller-coaster riding of Missouri. You’ll find Missouri offers Civil War history, terrific canoeing (at Eminence), and an excellent swimming hole (Johnson’s Shut-Ins State Park).
The route crosses the Mississippi River at Chester, Illinois, and heads into Carbondale, another fun college town. A ferry takes you across the Ohio River into Kentucky, where you’ll enjoy the evening fireflies at your campsites. Kentucky offers rolling white-fenced farms and woodlands until reaching Berea, the gateway to the Appalachian Mountains. A loop south of the route will take you to see Mammoth Caves National Park, the longest cave system in the world. Past Berea, you’ll spend some time ascending and descending the mountains of the Appalachians, and riding part of the Blue Ridge Parkway in Virginia. The mountains turn to rolling hills and then flat riding through lush plantations and farmlands. The last stretch of the route is rich in the history of the American Revolution, with Colonial Williamsburg as the highlight. Yorktown, situated on the Chesapeake Bay, is the route’s end.
Terrain Some stretches of the western portion of the route follow large river valleys and can be generally flat, but expect some climbing almost every day between Astoria, Oregon, and Pueblo, Colorado. The passes throughout the Rocky Mountains are generally long but not terribly steep. The descents from these passes are, of course, a blast. Most of Kansas is beautifully flat. Missouri through the Ozarks and eastern Kentucky through the Appalachians offers short, steep climbs. The Virginia portion of the route, surprisingly, has more total elevation gain than any other state.
Logistics Camping choices will vary across the country between small private campgrounds, city parks, state and national parks, national forests, and the occasional back yard. The northern Oregon coast is a heavily traveled tourist route and is flush with camping and service opportunities. From Oregon eastward through Kansas, you’ll find services limited mainly to the towns along the route. Carrying extra water in the West is a good plan. Camping options improve once you’re in the Rockies, but you should still expect some long stretches between accommodations and services. Options will increase near tourist areas such as Yellowstone and Grand Teton National Parks. Kansas is legendary for its hospitality. Camping in city parks is the norm through Kansas and Missouri. Food, water, and overnight accommodations are abundant from Missouri to Virginia.