At 54 lbs (and up), I wonder how realistic it is to do anything other than easy trails on an e-bike? My e-bike is also 55 lbs, and I find it difficult to do anything but the easy trails, but I'm also 76, so maybe I've lost my nerve?
At 70 years old, 6'2" and 315, I'm not your typical picture of a trail rider or somebody that enjoys exploring single tracks - but I've been doing it for over 50 years - on everything from ATV's (big and small), to snowmobiles, to motorcycles. Why should I want to change that when converting to an e-bike?
That said, my experience has shown this fat butt requires a lot of power when a bike I'm on is pointed up a big hill - even a paved one. I have 2 bikes at the moment and both are powered by motors that are well over 1000w. Call that an old habit I've no intention to break, or assurance if you like. The hub drive is a converted Rad City powered by one of the most powerful geared hub motors available (MAC 12t), and it rides on 26x2.1 Schwalbe Marathons. The new mid drive is powered by a Bafang Ultra motor - pretty much the most power available in a mid drive. It's currently on big 26x4 knobbies, soon to be converted to a street tread of the same size. These are both 70+lb bikes.
To the question, how realistic are these bikes are for trail riding? So let me say, they work for me! Do I think you need anything like this to go exploring? Oh geez, no way. Some of the trails I've found, some of my favorites, I can/do ride on PAS 0.
Trails come in all shapes and sizes. It could be 100' long and sugar sand from one end to the other that's used as short cut, or a true gem, a mostly level moss covered single track trail forming a tunnel through thick woods, it's entrances overgrown to the point they're nearly invisible.
The ONLY reason I know about either of these, is because I took the time to check them out after spotting them. My biggest point is, this has little to do with what you are riding. It's way more about your curiosity....
If it looks like you're getting in over your head (or your bike's), don't push it. Get off your bike and turn it 180 degrees and scout out the next trail. You may be surprised how many you drive by now without giving them a second thought....
-Al