You have a few different options here.
As for time lot depends on whether you are lucky to hit a bus stop or the boat dock at the right time. Obviously, if you don't have to wait for your transportation, you will get there faster. I would say to plan on an hour.
To go all the way by bus, take a bus from your resort to one of the parks (this is for Epcot, HS or AK not MK-for MK see next paragraph). When you get to the park, transfer to a Fort Wilderness bus. When you get to Fort Wilderness, you will be at the Outpost bus stop. You will need to Board an internal bus there, and go to the Meadows area. There are three bus routes (Yellow, Orange and Purple). All could get you to the Meadows, but the easiest would be Orange.
If you go to the Magic Kingdom by bus, you will need to board the Fort Wilderness boat (the dock is right in front of the MK entrance, which is a little bit of a walk from the bus stops). The boat will take you to the Settlement area of Fort Wilderness, where you will also need to hop on a bus to the Meadows (it is also a bit of a walk from the dock to the bus stop). Here, you will want an Orange or Purple bus. This option will involve more walking for you than transferring at one of the other parks.
You could also bus it to Downtown Disney, and get on a Fort Wilderness bus there, but considering that you are starting at the All Star resort, this is not your best option because of distance (all of the parks would be closer).
To go back, reverse the process.
And, if this seems like a big hassle, it is. So be sure you really want to see the campfire.
TCD
