You sure can. It is great fun. The Campfire sing-along/ movie is a jewel that does not get the same attention as some of the other night-time features at WDW. Just the way I like it!
The only downside is the movie ends pretty late if you stay to the end. Our kids are generally really tired by then (walked the parks all day, ate a buncha candy'n kid stuff). Disney internal transportation, pretty efficient on balance, "seems" to take longer when you and the kids are tired........
We usually take a cab back to our resort (if we aren't staying at FW) or drive our car (rental or personal) to and from FW.
OR
throw caution to the wind and take the FW internal bus up to Crockett's Tavern shortly before the movie is over, grab an adult beverage and watch the MK fireworks from the beach. Then take the boat to MK & bus back to our resort. This IS magical but requires some planning to keep the kids happy.