Whoops - most convenient -- yes, Uber/Lyft, or a shuttle like
SuperShuttle or
Primetime Shuttle
(edited per ParkHopper1's note below

)
Info from the Disneyland site:
Amtrak operates 7 days a week, 365 days per year, with 12 scheduled round trips. The Coaster operates Monday through Saturday. However, there is no service on Sunday, New Year's Day, Memorial Day, July 4, Labor Day, Thanksgiving or Christmas Day.
For more information on ground transportation options, schedules, fares and routes, please visit the following websites:
Public Transportation to the Disneyland Resort
Amtrak
Amtrak's Pacific Surfliner runs between San Luis Obisbo (in the central part of California's coastline) to San Diego (in the southern most end of Southern California) with multiple stops in between. If traveling from other areas via Amtrak, you will need to transfer to the Pacific Surfliner at any of the stops along the train route.
Once you arrive at Anaheim Station, you may transfer to the Anaheim Resort Transit Route 15 bus, which will take you directly to the Disneyland Resort, or you can transfer to the OCTA Bus Route 50 and exit at the Katella-Harbor Blvd. stop with a short walk along Harbor Blvd. (approximately 3 blocks) to the Disneyland Resort.
For more information on Amtrak's schedules, fares and route information, please visit the following website:
Metrolink
Metrolink is a rapid commuter rail system that serves Southern California. There are 7 lines that serve the area and include:
- Ventura County Line
- Antelope Valley Line
- San Bernardino Line
- Riverside Line
- Orange County Line
- Inland Empire-Orange County Line
- 91 Line
The Anaheim Amtrak/Metrolink Station can be reached directly via the Orange County Line, the 91 Line with a transfer to the Orange County Line in Fullerton and the Inland Empire-Orange County Line with a transfer in Orange. Travel via the remaining 4 lines requires a transfer to the Orange County Line at Union Station in Los Angeles.
Once you arrive at Anaheim Station, you may transfer to the Anaheim Resort Transit Route 15 bus, which will take you directly to the Disneyland Resort, or you can transfer to the OCTA Bus Route 50 and exit at the Katella-Harbor Blvd. stop with a short walk along Harbor Blvd. (approximately 3 blocks) to the Disneyland Resort. For more information on Metrolink's schedules, fares and route information, please visit the following website:
Greyhound
The Greyhound bus station is located at 100 W. Winston Rd in the city of Anaheim, less than a half mile east of the Disneyland Resort and is accessible from thousands of service locations in North America.
Once you arrive at the bus station, transfer to the Anaheim Resort Transit Route 10, which will take you directly to the Disneyland Resort via S. Anaheim Blvd. and Ball Rd.
You may also choose to take a quick ride via taxicab due to the Disney Resort.
For more information on schedules, fares and station locations, please visit the following websites:
Los Angeles Metro and Orange County Transit Authority
The Los Angeles County Metro and the Orange County Transit Authority OCTA operate a network of interlinked bus routes and rail lines that service Los Angeles and Orange County.