If you look at the way the connectors mate... it's not possible unless completely submerged... in which case you probably have other problems.
Yeah, the water drains around the connector and there is a drain at the bottom of the connector so no water pools. This is part of the reason why the Tesla guys were so surprised at Porsche going 800 volts, easier to arc in inclement conditions when there is that much potential. Not that 400 volts is safe, don't put your tongue on it. But that connector is designed to be beyond the capability of electricity to arc.
I think it depends on how much you're planning on driving in a typical day or week, or how much you're willing to spend on the project. If it's a "no holds barred" situation, I'd go 60 Amp circuit to a Wall Connector and call it a day. If you want to save a few bucks you could get away with a NEMA 14-50, slightly smaller cable, and a 50 Amp breaker. But I expect the Truck will consume notably more kWh/mile and the extra charging capability might come in handy more often than you might initially expect.
It might be advisable to have a separate meter for charging EV(s) and may be hot water for shower, using off peak rate and a second meter for daily house utilities with a regular meter rates for cooking, heating, Air Conditioning to avoid peak rate. Also do you plan to have solar panels and PowerWall ? Even if you don't plan (yet) having such installation, you can get some good information from the following video. For example adding an isolation switch from the grid might not be a big cost when building a new house, but could be an expensive requirement if you plan to go solar later on.