Some recumbents are higher than others. For some (eg ICE) you can get additional supports to help get in/out. Just because some recumbents are low does not mean they all are.
I've not ridden an upright trike but from what I've seen they are not as easy to ride as recumbent trikes - but others might have more experience.
In terms of width measure the door user will want to get it through and look at specs and/or post width of door here and people can maybe measure their own.
An 'upwrong' trike is a whole different kettle of fish to ride, it's a misnomer that balance isn't required, when it still is,in fact you need to counterbalance & counter steer, which perversely requires a sense of balance.
Which is where the low sense of gravity comes in with recumbent trikes it's not such a requirement, but you still need to shift your weight if cornering at speed, thin back to your days wasted tearing about on a soap box cart....it's the same feeling.
And honestly, being visible or not. Isn't a thing , believe me you are far more visible on a recumbent of any type, just because they are so unusual to see on the roads