Almost every new bike, esp old school cup and cone and threaded headsets, I've taken it apart and greased and adjusted everything to my satisfaction...always seems they put the absolute minimum amount of grease in there...greased the headset bearings and fork, wheel bearings, bottom bracket (even on sealed bearings, it is often recommended to place a bead of grease around where the seals and crank shaft meet), seat post, and pedal bearings. A grease needle attachment is worth buying and makes things easier. Doesn't take that long to do it, although if you have a freewheel, you need a tool to take it off to grease the rear bearing on that side and one should grease the freewheel threads before reinstalling it. Would pay to have the wheels checked for trueness, spoke tension, and if it's properly dished. As mentioned above, cables will need readjusting periodically for both the brakes and shifter/deraileur. Have done this for some of the kids around my neighborhood with store bought bikes and they are happy as all heck with the smoothness and longer coasting times/distances. The brake pads are pretty crappy, mark up the rims, and wear quickly...buying Kool Stop Salmon pads is a vast improvement when it come time to replace the OEM ones. For the chain, I buy a can of Dupont Teflon Multiuse lube from Lowe's for $5.00...spray it on and let it dry...leaves a waxy like coating.
The Ranger Bike is a decent low cost bike, although there are many at this forum that would disagree. Seen a lot of them over the years around my area and many are still going strong with the original owners or as hand me downs to their kids or younger siblings. Can buy a higher end bike later (new or used) if she stays serious about riding a bike or out grows this one.