How many days are you planning for driving?
Where will you sleep in between, and once arriving? I think when you can arrange to sleep somewhere in your room, instead of sleeping in your car, that would be fine (to have access to power).
To keep him warm you can use (when you have access to a microwave where you sleep) a cherry seed pillow or similar that you can heat up and pack in his carrier. Also self-heating hand/feet warmer are a solution. Where you sleep, you can also plug in the lamps for some time during evening.
And I'm sure in the car you will maintain a temperature that is okay for you too and not freezing temperatures, so no danger for your dragon.
It will likely stress him a bit. But being given to another person, having a new environment (even if the person cares well), but even maybe the new person will not care well for him will also stress him. And being a few days without optimal but okay-ish conditions is not dangerous. Unpleasant yes (like a bad weather period in nature), but not dangerous as it might be e.g. for some fish when the conditions cannot be met.
Another option might be flying, if the reason for driving is not that you have to get your car to your new location. In that case, the dragon must go into the cargo hold like your other pets would need to, but it would be only one "not so comfortable" day for your dragon. Whether there are some airlines in your country that take reptiles is something you would have to look up, but likely they are.
How I would decide:
If I had to move and could not leave my dragon with a person I trust 100% that they keep the optimal conditions long-term, I would take my dragon with me as far as permitted. Better a few non-optimal days than a non-optimal rest of his life. If I could leave him with somebody who keeps everything right I might rather leave him there. (Let's say I would have to go for a year or so to another location for work, or some months for helping my parents and my husband would stay at home: dragon would stay with him. Both my husband and me leaving: dragon would go with us as far as permitted (might not be permitted into foreign country, or if he must go through long quarantine I would have to find another person that takes him and I would worry very much).)