Alamo's old off-airport facility was hell and gone from the airport; the shuttle bus ride was about 15 minutes in the opposite direction from WDW! But Thrifty's facility is much closer, barely off the airport's property at all. The bus ride is only about 5 minutes, and the wait is seldom more than 10-15.
Definitely join Blue Chip. It lets you avoid the lines. If there is nobody at the Blue Chip counter when you enter the building, just wait for a moment, someone will be along quickly.
Pocohontas2004, remember - No rental car company reserves a specific make and model of car, they only reserve a particular class of car. Check your ressie again and I'm sure you will find it worded the same as every ressie I have ever made: "Premium (Chrysler Pacifica or similar)" You will get a similar vehicle - a car of similar size - but you are not guarnateed to get a Pacifica. If nothing of the class you reserved is available, you will get the next higher class of vehicle at no extra charge.