You can make it from Downtown Orlando and the other six largest metropolitan areas (Orlando is #4) in the Southeast USA to Walt Disney World in a day's drive (well, obviously Orlando and Tampa, that goes without saying since they are in such close proximity!), although outside the Southeast USA (and perhaps even outside Florida if you have the money for multiple people or are only one person as flying is often cheaper than driving for one person) I highly recommend you fly.
Theme park tickets are not cheap! Resort hotel rooms are even more expensive! I would know because I am planning a trip for my mother, my younger brother, my sister-in-law, my ex-sister-in-law, and my two nephews for my mother's 72nd and my older nephew's 13th birthdays, and I fully expect to pay $25,000 for their trip....if not more! Expect to shell out multiple Benjamin Franklins for your vacation as well! If you're not affluent and / or have saved up, you could find yourself shell-shocked!