we always do a couple, my children are young also 7,4,1 and dont do well in lines to begin with so we save lines for rides and have the characters come to our table in an airconditioned resturant! remember to do ADR so you dont have to wait to long for your table...my experience is no longer then a 5-10 minute wait. we always show up a few minutes early.
another thing to remember at the character meals the characters will take time if your child is frieghtened...maybe even coming back by to see if they have warmed up. if you wait in the park you'd have to go back to the end of the line to try again.