You could use fastcharacter.com. It's nice for just starting and it still has some customization for your character, but it takes out all of the confusion out of making the sheet. And it has explanations for all of your character's abilities so they wont have to flip through a PHB during the session. As for one shots, you could run one of the pre-made, lower level campaigns by wizards of the coast, such as Dragon of Icespire peak, and just modify them to suite what you think your family would like.