Thule roof box
We normally travel with 3 small dogs however we now thinking of taking one of the cats with us however this means she will need her own cage.
In the vehicle we carry a mobility scooter which takes up a fair amount of room and is directedly behind the driver's seat. That plus the awning, cool box, clothes bag, food carrier and a few othe things leave very little room for a cage for the cat. The
dogs always seem to find spot on top of the items to sleep. 
We are thinking of a Thule 100 roof box on top of the Jeep Grand Cherokee for the awning which will then free up a lot of room.
The question is not about the roof box itself but rather loading and unloading a roof box as I struggle to lift my arms up high due to arthritis. The wife can manage and teh awning weighs 21.4kgs. Being a 4 x 4 it is a bit higher than normal cars but lower
than a lot of other 4 x 4s.
I was thinking that if we have the doors closed and awning packed, if we then "rolled" it up the side of the vehicle and into the box. I can help using my sticks to propel it a bit more however we do have one of those very lightweight step ladders (1.8kgs)
which cna live under the fixed bed in the caravan.
We are not sure how practical this will be for us and are hoping that someone who has a roof box and uses it regularly can advise on loading and also removing the unit entirely off the vehicle during the winter months. It will only be used for the awning.