McCarver left Oregon for the California Gold Rush in August 1848, but left his family in Oregon City to hold the land claim. In 1849, he claims to have helped to found Sacramento, where he constructed housing to rent out. McCarver was then elected to a legislature designed to govern the city on April 30, 1849. He was also elected to serve at the Constitutional Convention of 1849 that was held in Monterrey, as one of eight people representing the Sacramento district. Also in 1849, along with some others, he purchased three passenger ships, including the "Ocean Bird". The "Ocean Bird" was then put into service between San Francisco Bay and Milwaukie, Oregon. Due to flooding and fires, McCarver decided to return to Oregon aboard the "Ocean Bird", bringing with him a house that had been cut in Boston. This Aladdin House was then constructed in 1849 on his farm near Oregon City. His farm became known as the Locust Farm. During the Rogue River Wars of 1855 to 1856 McCarver served as commissary general and set up his base at Roseburg in Southern Oregon. McCarver also participated in a gold rush in Idaho in 1862, setting up a company in what became Idaho City. In March 1868, McCarver then moved north and helped found Tacoma, Washington. He first went to Olympia, capital of the then Washington Territory, and procured a map to study the area and consider the most likely terminus of the then planned transcontinental railroad. On April 1, 1868, McCarver arrived at Commencement Bay, a likely railroad terminus on Puget Sound due to its proximity to Snoqualmie Pass, and then purchased the land of Job Carr. He continued buying up available land along Commencement Bay in anticipation of the railroad. McCarver also convinced Hanson, Ackerson & Company to build a sawmill in the area while he platted a town site and sold-off lots. McCarver wanted to call the city Commencement City, but after a suggestion by Philip Ritz of the Northern Pacific Railroad, McCarver changed his mind. Anthony Carr, Job's son, had already filed a plat for "Tacoma" on November 30, 1869. McCarver chose to call his neighboring plat "Tacoma City," when he filed his plat map on December 3, 1869. The word "Tacoma" may be the purported Native American name for nearby Mount Rainier.