To chime in and reiterate some points: Steel and 36 spokes are a great combo. In my early days on my old (and still running) Trek mtb, I "warbled" the back wheel (in retrospect, it may have only needed truing) and invested in 36 spoke Ryno rims. I was a 255lb hefty back then. Less than a decade later, through the ups and downs of my weight, I am +/- 170lbs and healthy. Hills and distances get conquered in time. You've already made admirable gains. Even on my MANY days I DIDN'T WANT to get on that thing, I found out that the exhilaration of being my own motor and movement was worth getting over myself. I now vastly prefer cycling over any other mode of locomotion.

Congrats on your choices! (Oh, on that seat height: You should sit high enough that you don't quite lock your knees at the 6 o'clock positions when pedaling. When you stop, if possible, lean to one side and rest on one foot; like the experienced cyclists/motorcyclists do. If not able for now, reduce seat height only as much as needed to operate the pedals/mount the bike.)

Drive Side
1995 Trek 800 Sport