I get a big fresh picnic leg on sale, put it in a big pot of water with a bottle of barbeque sauce (will get them on sale) and let it cook all day at simmer after it boils...
then take out of pot, pull apart with two forks, put back in pot with some of water and two more bottles of barbeque sauce and cook longer... adding more cooking water if needed but not too much to make soupy. (keep the water if you can because it soaks in if you wait until next day)
let them put on rolls themselves and done
Oh, at one picnic, a girl used hot dog roll instead of hamburger and it actually worked better. Didn't fall apart as she ate it.
Can get hot dog or hamburger buns on sale and put in freezer until needed.