What's your thought, I'd be safer in the trike than on the road
tandem, or should I start planning my funerals?

The whole problem here is that a trike takes up much more road space
and it makes it more difficult for another wide vehicle (an
automobile) to pass, basically requiring the cars to slow down from
what you said is 45 mph to probably less than 18 mph until there is no
one in the opposing lane so they may pass safely. If the road is as
busy as you say it will be very inconvenient for the faster traffic
and they will get mad at you. I doubt they will try to kill you.
However, on a tandem you are very narrow and no one has to change
lanes to pass, and you could potentially travel much faster being
lighter with twice the power of the tricycle.

I would go with the tandem and travel that road with reckless abandon.

Ted