"Connection" is single word alternative for "another place things could go wrong". If there are hard and fast business reasons why you have to be in Glasgow before a fixed date, then scrap everything and book the direct. It is not like there is nothing to see, do, or eat in Glasgow. Or even Edinburgh is only a two-hour train ride if you have a bit of flex time. (We chose against the train ride to Scotland from London a year ago because of reports that track rebuilding on the West Coast Line was frequently (meaning most of the time) causing very significant delays. Not sure if the work is still ongoing or completed).

Now if half the trip is the journey and you just want to ride the A380 just to be different and just want to take the sleeper because you never have and you just want to Amtrak to New York and sleep in your old room to revisit the past just because; then do it. All of those are good enough reasons. (Not to mention doing all of the same quirky self-actualizing things on the way home when there is no time pressure is an alternative or even a better option).

Having finally visited my Scottish and English roots a year ago I am jealous of your less time-consuming flight time from the east coast. We left a few things undone, but not much, and too soon to book a complete re-do of everything. The additional travel time from Texas is just enough to make it something you can't just do on a whim for a few days to see a few things and fly back.