You have a awesome platform. First I'd the care of all the bearings. Carrier, front wheels, steering. Do the brakes, chain and sprockets, change the cable's. I would do all the maintenance stuff first. As far as add on's, extended axle, nerf bars, bar risers( if she is comfortable with them) repack silencers. I'm going through the same thing with my girlfriend. I don't know where you want to go with this but that's all stuff I did with her bike.