The best place for do the trail is from Los Albergues,this is over Pradollano, the trail from this place is very very easy,if you fallow the road in direction to Veleta.
Don´t necessary climb to Veleta for go to Poqueira,you continue the trail to Cariguela and continue to La Caldera,in this point the trail go to Poqueira without loss,the time for this trail is aproximately six o seven hours,this time is for go,for back in the day is nine hours....
I hope this infomation will be util for you.
Excuseme for my English is very bad.
Wellcome to Sierra Nevada and ggod trip.