90 day report is good. If you try online and it says contact office then maybe,
Don't worry too much they will want to hear your side of the story first before they actually arrest you so it may just be an order to attend and hear charges.
If you are just passing through your original country of departure sets the rules. If you have spent 21 days + in another country then that can be treated as your country of departure.
There will be a scheme in place at Phukhet. Book and pay for 2 PCR tests and 3 days ASQ plus Admin fee around 15,000 baht and they will put the pass on your phone there and then. !!
Roojai insurance do a breakdown service for cars under I think 15vyears old. It's not quite AA or RAC standards it's more a Green Flagging!!! But better than nothing.
You can but as was recently discovered by a Canadian couple in Phukhet you may still get caught up in the testing scams. 2 tests at 3800 baht a time in each province you visit!
Ever since the announcement that Thailand was opening up from 1st October some immigration offices are waiting until nearer that date to decide on Covid extensions. Good news is that I understand a 7 day extension will be given on request free of charge.