The bad ones I've been on are:

• between old small town stations, so now it's suburb to suburb and you can't access anything in between so they're useless for commuting. If the rail-to-trail revamp continued on it would go on through the former rail hub of the local large town, but that part hasn't been built out yet, and may never be because at some point they'll have to deal with crossing (hopefully over / under) highways and stroads that have been built up since.

I have a proper bike trail in my home city that goes along a river and it's amazing that it winds along for dozens of miles with stuff to look at and breezes. You're not confined to a corridor with overgrowth on both sides causing stifling heat that's trying to imitate a highway. It's a pleasant commute if you happen to live along it and a relaxing recreational ride if you're not.

• long gradual grade. Coast one way, which is nice, Sisyphean bike ride with no rest for miles the other way.

I might've come off harsh, I do generally like rails-to-trails. They're better than nothing, and you're right that having an ebike takes the arduousness out of it, but they're very much a hand-me-down version of proper infrastructure. I would rather have the passenger light rail service.

In the 1900s the small MS town I'm thinking of had a few hundred people and a rail station. You could pay the inflation adjusted ~$15 for all the transfers to go back and forth to the coast ~100 miles away. We didn't discard passenger rail in the US because it wasn't useful, but because it was hard to extract profit out of the public service.