I don't think any of that is relevant, since i'm looking for a training plan & tips on how to approach back to back long rides.
but
I did a metric century last year. I've been on the trainer in the basement all winter, resumed commuting to work recently, and did a couple 40 km rides so far this year.
Route is mostly flat S. Ontario
Riding an aluminum specialized Sirrus that I converted to drop bars over the winter. This is the bike I did a metric on last september.