There are several methods to get to the Grand Canyon's South Rim including shuttles, tours from outlying cities, a train, and even a few flights. The North Rim has a seasonal shuttle that runs once a day, and people doing guided Rim-to-Rim hikes can go through a guide service that includes transportation. That being said the best way to see Grand Canyon National Park without restriction is to have your own vehicle.
Grand Canyon Airport
Although there are a few flights from Las Vegas to the South Rim, these flights are run by tour companies and are both expensive and unreliable since they would rather have you pay for a scenic flight. Nearly all of these scenic flights originate from Las Vegas, where you are typically shuttled from your hotel to either the Las Vegas, or Boulder, NV airports before your flight to the South Rim/Grand Canyon International Airport. Those who don't mind spending the extra money can also charter a plane from Las Vegas, Phoenix, Flagstaff or Sedona to the Grand Canyon Airport on the South Rim. If you have your own plane, the Grand Canyon Airport is public so you are able to fly in yourself.
Flagstaff is the closest city to the Grand Canyon, and the only major city in Northern AZ. The Flagstaff International Airport is small and convenient, but it will typically cost $100-$200 more per ticket than the Larger Phoenix and Vegas Airports. Nearly all Flagstaff flights originate from Phoenix, and are run by US Air.
Phoenix is a large international airport with flights from pretty much anywhere in the world. It is also where most flights for Flagstaff Arizona originate with US Air. Phoenix Airport is easy to get around in, and you can pick-up shuttles, charters, rentals and pretty much any type of transportation you need upon arrival at the airport. Phoenix is about 3.5 hours from the South Rim, and 4.5 hours from the North Rim.
Las Vegas Airport
Las Vegas is a hub airport and the place where most international travelers fly into, both because of ticket prices, and because they want to see Las Vegas. Las Vegas Airport is easy to get around in, and you can pick-up shuttles, charters, rentals and pretty much any type of transportation you need upon arrival at the airport. The drive from Vegas to the North Rim or West Rim is about 3.5 hours, while the South Rim is about 4.5 hours.
There are several shuttle services that run from Phoenix and Flagstaff to the South Rim seasonally. These shuttles run several times a day, and you can also get connecting shuttles from Camp Verde and Sedona AZ.
North Rim Shuttle
The Trans Canyon Shuttle runs seasonally from the North Rim to the South Rim of the canyon, with two trips daily from North to South and from South to North.
West Rim Transportation
There is not a scheduled shuttle from any major city to the West Rim/Grand Canyon Skywalk. There is however a park and ride shuttle about an hour from the West Rim outside the town of Meadview. This shuttle will save your car from a long stretch of bumpy dusty dirt road. There are also several tour companies that run from Las Vegas to Grand Canyon West including Jeep Tours, Bus Tours, and Scenic Flights.
The best way to visit the Grand Canyon unrestricted is by having your own car. This is especially true for areas outside Grand Canyon Village on the South Rim. Although there are several rental companies scattered throughout the Grand Canyon Area, the best and most reliable cities to pick-up a vehicle are Flagstaff, Phoenix, and Las Vegas.
Taxi & Charter Services
It is possible to get a taxi from Flagstaff to the South Rim, but it will cost you. There is a 24-hour taxi service at the South Rim that will take you to or from various South Rim locations and Tusayan. There are several Charter Services in Phoenix, Las Vegas and Sedona that you can hire to take you pretty much anywhere you want to go.
Park Shuttle Buses
There are free park buses available on both the South and North Rims of the Grand Canyon. The South Rim bus has 4 routes that take you to all the major destinations on the South Rim. These routes go along Hermits Rest Road, Desert View Drive, throughout Grand Canyon Village, and to the South Kaibab Trailhead (used frequently by hikers). The new Tusayan Grand Canyon shuttle runs seasonally from the small town of Tusayan to the National Parks Visitor Center. The shuttle was initiated to help cut back on traffic in the Park, but the small size of the parking lot certainly has its limits. Tusayan is only a few miles from Grand Canyon National Park, so this could work to your advantage if you're staying at one of the town several hotels, or don't want to deal with South Rim traffic. The North Rim shuttle only has a short route, but most places in the North Rim village are only a quick walk.
Grand Canyon Railway
The Grand Canyon Railway goes from Williams Arizona, to Grand Canyon Village on the South Rim. The Train Ride is actually a tour, but if you like trains and don't want to make the 45-minute drive from Williams this is certainly an option.