All theme parks have tram service to the entrance except the Magic Kingdom. At the MK, you will take a tram to the TTC and then either take the monorail or a ferry to the entrance.
Sometimes you can walk to the front entrances. It really depends on how close you end up parking to the entrance. At AK, we almost always are able to walk, but at the others we almost always take the tram. Where you park is also dependent on what time you arrive.