I also use apple when I smoke a turkey. I find that two hours of smoke gives a good smoke flavor.
You don't want to baste the turkey while it is in the smoker. You want to keep that door closed, and only open when absolutely necessary. Each time you open the door, you allow heat to escape which adds additional time to the full cook time.
I've only tried to capture the dripping once for gravy, but by the end of the cook everything evaporated in the pan. I suppose you can add some low sodium chicken broth to the pan you want to capture the dripping in. If you want the dripping for gravy, or dressing; the cavity collects a lot of juices, just be careful how you take the turkey out of the smoker to avoid spilling the juices on the floor. Have a rimmed sheet pan (cookie pan) to carry the turkey indoors.