We had an issue like this following a crash on our way on holiday, with a boot full of everything you need for a fortnight in a holiday cottage with three small children (quite a lot of it just fitted in round other things, not bagged up or packed properly), and two bikes on the roof of the car (the two on the back were written off in the crash).
We were hours from home and hours from our destination, and our insurers best offer for a courtesy car was a Vauxhall Corsa! For five of us, two on boosters (this was a long time ago - children were on boosters from about age 4), and one in a car seat.
When we said this was utterly unsuitable they huffed a bit and said 'well - you sort out something suitable and bill us!' - so we spent an hour ringing round - and as it was Saturday afternoon, we struggled to find anywhere open with a suitable car, and in the end, we had to schlep all the way from Retford to Newcastle airport on the train, with all the cases, gubbins and 2 bikes.
Dh had to wait for the recovery truck to pick up our car, so I took ds3, who was quite small, and a pile of stuff on the train, including a change of trains, and got a taxi to the airport to pick up the car and drive back into Newcastle to pick up dh and the other two dses from the station.
It was a total nightmare of a journey. However, huffiness apart, the insurers were pretty fair. They accepted we had to spend a night in a hotel, instead of driving on to our destination that night (it was gone 6pm by the time we were all reunited at Newcastle and we'd been on the go for 9 + hours so it wasn't safe for dh to drive on), and paid for that, the hire car and the new carrier for the bikes as well as replacing the destroyed bikes and repairing the car.