Yes, we almost always stay offsite and resort-hopping is one of our favourite pastimes. As HeatherPage says, no-one at WDW will question you as to your authorisation to use the free transportation. We're Annual Passholders, but the WDW Official Website does not seem to make any distinction with regard to ticket type/transportation privileges:
Q: What is the best way to get around within the Walt Disney World® Resort?
A: There are many modes of transportation within the Walt Disney World Resort, including Bus, Boat and Monorail. A rundown of transportation within the resort:
By Bus:
Most areas of the Walt Disney World Resort are accessible by bus from other areas within the Resort, including Theme Parks*, Water Parks, the Disney Resorts and the Downtown Disney® area. Buses travel on routes throughout the Resort and do not provide direct service between all destinations.
*Magic Kingdom® Park is not accessible by bus from Disney's Contemporary Resort, Disney's Grand Floridian Resort & Spa and Disney's Polynesian Resort. These Resorts provide monorail transportation to the park.
By Boat:
The Magic Kingdom® Park is accessible by water launch from Disney's Contemporary Resort, Disney's Grand Floridian Resort & Spa, Disney's Polynesian Resort, Disney's Fort Wilderness Resort & Campground and Disney's Wilderness Lodge. The Disney ferryboats connect the Magic Kingdom Park to the Transportation and Ticket Center (adjacent to Magic Kingdom parking).
Epcot® and Disney-MGM Studios are accessible by boat from Disney's BoardWalk Inn and Villas Resort, Disney's Yacht Club and Disney's Beach Club Resorts and the Walt Disney World Swan and Walt Disney World Dolphin Hotels.
Downtown Disney® is accessible by ferryboat from Disney's Port Orleans Resort and Disney's Old Key West Resort.
By Monorail:
Disney's monorail runs between the Magic Kingdom Park, Disney's Contemporary Resort, Disney's Grand Floridian Resort & Spa, Disney's Polynesian Resort and the Transportation and Ticket Center (adjacent to the Magic Kingdom parking lot). A connecting monorail takes Guests from the Transportation and Ticket Center to Epcot.