konung wrote: 1) What are best / worst times to drive? When is it better to stay at home / stay longer at the beach or leave late / early, to skip traffic?

STT is a busy place especially in CA as the Cruise Ships arrive and depart. Pretty much the same hours to avoid in Chicago or require a little additional patience. STJ traffic is usually not a big deal but there is some major construction going on in downtown cruz bay. They are putting in a traffic circle

konung wrote: 2) Does it change from season to season? ( Low / High Season) Cruise Ships?

Yes, but when the ships are in the ships are in. Summer you usually don't have 6 ships in. Watch the Cruise Ship Schedule on this page.

konung wrote: 3) Roads to avoid / take? Again I'll give Chicago as an example - there is Interstate 90 - that is better to avoid at all times ( you can get in a traffic jam at 2 am on Wednesday Morning - I was picking up my friends from the airport recently - and we spent an hour in traffic in the middle of the night)

You will be on island there is no escape! 😉

konung wrote: 4) If I'm on a day trip to St. Thomas / St. John and I'm late for a ferry, is it possible to spend a night in the car? On the beach? Would there be problems with police?

The last ferry runs at 11 PM. If you miss the last car ferry then I would ride the hourly ferry back to STT and sleep in my own bed.

konung wrote: 5) What time do the beaches close on the islands? Parks on St. John? ( the reason I'm asking is that in Chicagoland - you can't stay on a beach ( on Lake Michigan which is quite warm and nice in the summer) past 10 or 11 pm, the park rangers or police - will boot you off.

Park Info - I think this will help