Alright, I'm a bit confused. I assume PNS is Pensacola, Florida, but by MCO do you mean you are catching a Greyhound bus from Pensacola to the Orlando Greyhound bus station (On John Young Parkway), or are you trying to get a bus from Pensacola to the Orlando International Airport (MCO)? These are two very different locations in Orlando; In Greyhound codes, MCO appears to be located someplace in Oklahoma. So far as I know, Greyhound does not serve the Orlando airport, though I could be mistaken.
From the Orlando Greyhound bus depot, I'm sure there are taxis available, or you could make prior arrangements with a towncar service, of which several are discussed on these boards. If you have very little luggage, there are Lynx public buses also.
Disney's Magical Express is unfortunately only available to persons traveling to/from the Orlando Airport (MCO), with no accomodation for rail or bus passengers.