A couple of points.
Motorways are statistically the safest roads. Autobahns with no speed restrictions, moreso. Driver attention and discipline is key.
Modern cars have technology such as "Speed Limit Assist', a camera based system that views speed limit signs, fixed, variable and temporary such as in roadworks and no entry signs. If the camera cannot identify the sign the prevailing limit is shown. This is the same as APNR and is character recognition, so if signs are incorrect to the legal definition, you have a non legal speed limit.
The biggest hazard to driving is food additives such as preservatives, and medication that delays response time within the human brain. Lots of proven research has been done on this, particularly in the US and Canada where the introduction of speed cameras increased the accident rate as peoples reaction slowed and rear enders far from the camera site were shown to occur. This research has been quashed by governments.
The old 'speed kills' message has recently been proven to be false. Tim Peake travelled at 17,500mph in space, he survives today inside the ISS. Speed does NOT kill. The rapid acceleration of your primary organs inside your head and skeletal frame is the cause of death.
Towing a caravan is primarily for going on holiday. You have no time pressures to meet. Enjoy the journey as part of the holiday.