Glenn,
Eyepieces depend a bit on which scope you select as they have different focal lengths and with produce differing magnifications and field of views on each lense. So a hint in that direction will help us to advise you a bit better.
As for other stuff a red torch, a planisphere, a chair for observing (I use a fold up camp stool), a step for the lad to use when the scope is too high for him, a cheshire eyepiece for collimation would be the basics. Also a box to throw it all in when disappearing out the back
