Question: The Trapper's Trail links the Great Platte River Road at Fort Laramie and a trail pioneered in 1821 by who?

Context paragraphs:
Laramie-Poudre Tunnel: The Laramie-Poudre Tunnel is an early transmountain tunnel in the U.S. state of Colorado.  The tunnel transfers water from the west side of the Laramie River basin, which drains to the North Platte River, to the east side Cache la Poudre River basin that drains to the South Platte River.  The tunnel is about 11500 ft long with variable diameters with a minimum diameter of about 5.3 ft .  The diameter varied due to the different material mined through and the erosion of almost 90 years of water flow.  It is located at about 8400 ft elevation with about a 1.7 degree down slope.  The Laramie River lies about 225 ft higher than the Cache La Poudre River at this location separated only by a mountain ridge.  The Laramie-Poudre Tunnel is located about 45 mi west-northwest of Fort Collins, Colorado, about 20 mi south of the Wyoming border and about 25 mi north of Rocky Mountain National Park.  It was built between 1909 and 1911 to convey water from the Laramie River to the Poudre River for Front Range irrigation.  Court battles between Colorado and Wyoming over water rights prevented operation until 1914 (Case 1995).

Trapper's Trail: The Trapper's Trail is a north-south path along the eastern base of the Rocky Mountains that links the Great Platte River Road at Fort Laramie and the Santa Fe Trail at Bent's Old Fort.  Along this path there were a number of trading posts, also called trading forts.  It was an important trade route for animal trappers and fur traders in the North American fur trade from about 1820-1846.

Great Platte River Road: The Great Platte River Road was a major overland travel corridor approximately following the course of the Platte River in present-day Nebraska and Wyoming that was shared by several popular emigrant trails during the 19th century, including the Trapper's Trail, the Oregon Trail, the Mormon Trail, the California Trail, the Pony Express route, and the military road connecting Fort Leavenworth and Fort Laramie.  The road, which extended nearly 800 mi from the Second Fort Kearny to Fort Laramie, was utilized primarily from 1841 to 1866.  In modern times it is often regarded as a sort of superhighway of its era, and has been referred to as "the grand corridor of America's westward expansion".

Guernsey Dam: Guernsey Dam is an earthfill dam on the North Platte River in Platte County in the U.S. State of Wyoming.  The dam creates Guernsey Reservoir, the last of the 5 major reservoirs on the North Platte River in Wyoming.  The dam contains a hydroelectric plant capable of 6.4 megawatts of electricity.  The total capacity of the reservoir is 71040 acre.ft of water which is used mainly for irrigation.  Morrison-Knudsen (Now URS Corporation) and Utah Construction Company constructed Guernsey Dam and the hydroelectric plant as part of the North Platte Project to provide irrigation to eastern Wyoming and western Nebraska.  Guernsey helps control the river flow and stores water released from the project's primary storage upstream at Pathfinder Reservoir.  About 8 mi downstream of the dam the Whalen Diversion Dam diverts water into the Fort Laramie and Interstate Canals that service farms in Wyoming and Nebraska.

Colorado War: The Colorado War was fought from 1863 to 1865 and was an Indian War between the Cheyenne and Arapaho Nations and white settlers and militia in the Colorado Territory and adjacent regions.  The Kiowa and the Comanche played a minor role in actions that occurred in the southern part of the Territory along the Arkansas River, while the Sioux played a major role in actions that occurred along the South Platte River along the Great Platte River Road, the eastern portion of the Overland Trail.  The United States government and Colorado Territory authorities participated through the Colorado volunteers, a citizens militia while the United States Army played a minor role.  The war was centered on the Colorado Eastern Plains.

Fort Laramie National Historic Site: Fort Laramie (founded as Fort William and then known for a while as Fort John) was a significant 19th century trading post and diplomatic site located at the confluence of the Laramie River and the North Platte River in the upper Platte River Valley in the eastern part of the U.S. state of Wyoming.  It was founded in the 1830s to service the overland fur trade during the middle 19th century.  It sat at the bottom of the long climb leading to the best and lowest crossing point at South Pass into western descending valleys and so was a primary stopping point on the Oregon Trail.  Along with Bent's Fort on the Arkansas River, the trading post and its supporting industries and businesses were the most significant economic hub of commerce in the region.

Platte River (Iowa and Missouri): The Platte River is a tributary of the Missouri River, about 200 mi long, in southwestern Iowa and northwestern Missouri in the United States.  It is sometimes known as the Little Platte River to distinguish it from the larger Platte River, also a tributary of the Missouri, in nearby Nebraska; the Platte River of Missouri itself has a tributary known as the "Little Platte River".

Great Platte River Road Archway Monument: The Archway (also known as The Great Platte River Road Archway or Kearney Arch) is a museum of and monument to Nebraska's and the Platte River valley's role in westward expansion.  The Archway is directly over Interstate 80 three miles (5 km) east of Kearney, Nebraska.

Santa Fe Trail: The Santa Fe Trail was a 19th-century transportation route through central North America that connected Independence, Missouri with Santa Fe, New Mexico.  Pioneered in 1821 by William Becknell, it served as a vital commercial highway until the introduction of the railroad to Santa Fe in 1880.  Santa Fe was near the end of the El Camino Real de Tierra Adentro which carried trade from Mexico City.

Fort Laramie, Wyoming: Fort Laramie is a town in Goshen County, Wyoming, United States.  The population was 230 at the 2010 census.  The town is named after historic Fort Laramie, an important stop on the Oregon, California and Mormon trails, as well as a staging point for various military excursions and treaty signings.  The old fort was located south of town across the North Platte River, at the mouth of the Laramie River.

Supporting paragraphs: Trapper's Trail Santa Fe Trail
Answer: William Becknell