As i used to work in Occupational therapy, a few pointers, everything everyone above has said is correct, but for the ramp make sure you coat it with some sort of non slip tape or paint, or even thickly apply paint and sprinkle dry sharp sand on it, to make it non slip, ramps when damp or wet are dangerous for the pusher.
The steeper the ramp the shorter it is the harder it is to propel somebody up it, and the FASTER they roll down it, not very much fun for the user,
Depending on her mobility,it may be of use to get a length of 18mm ply about 3 foot long and 12 inches wide, slope off the edges, and radius the corners, this you use as a sliding board to transfer her from wheelchair into car or bed etc,plas one end on wheelchair and other on seat, and she can then slide,
Always apply both brakes when wheelchair is static, easy to forget, but very alarming for the user.
Check the width of door some internal doors are to small for wheelchairs, best to remove them, or see if you can open them wider, by moving furniture,
Remove all rugs and loose mats, as they can stop a wheelchair,
Remember she may not be able to reach the kettle, so place it on a lower table with the tea and coffee when youre not there to make drinks,
User propeled wheel chairs, big wheels have beter mobility than the samller wheels,
have a bike pump handy to pump up the tyres, the chair will move easier,
be VERY PREPARED, FOR WHEN YOU GO OUT TOGETHER, FOR IGNORANT IDIOTS TO ASK DOES SHE TAKE SUGAR,WHEN YOU GO FOR A MEAL OR COFFEE,OR TO SAY SO YOUNG TO BE IN A WHEEL CHAIR, ALONG WITH BLOCKING YOUR WAY,
Apply some hazard tape to the top and sides of the ramp, so you can see it is there, or you or visitors will fall over it, i did frequently,
Its backwards down kerbs,and either tilt back to go up, or backwards but almost level going up the kerb, or youll eject the user from the chair,
Finally B and Q will cut timber free of charge to size from a sheet, so makes transport easier.
Best wishes to your Girlfreind in her recovery.