What's your budget?
For a traditional styled bike that is actually usable as a mechanical bike too, Check out the Trek Allant+. It has a nice mid drive Bosch drivetrain and is nice and efficient. I think they're $2500-3500. Not a budget e-bike, but not a Lemond either.
I just bought a heybike Ranger on Amazon for $1400. It would be PERFECT on your trails. However, this is the kind of e-bike that triggers snobbery from some of the folks above. It's got 4" fat tires on 20" rims and a 500 W motor; it weighs 71lbs. I can only reasonably pedal it unassisted up to 10 mph for any length of time. Only the first couple gears. On the other hand, I can put in as much or as little effort as I want and get up to 27 mph on level ground. That's in the highest gear, full assist pedaling crazy fast. I think it's really fun, and if you're not getting a workout, it's because you're lazy, not because the bike won't let you. This is the more common and affordable type of e-bike, with a brushless motor and planetary geartrain in the rear hub. When you start pedaling a hall effect sensor detects it and assists to whatever level you've got the PAS (Power Assist System) set to. I have mine set like so:
0 - Pure mechanical; emergency mode.
1 - 4 mph
2 - 7 mph
3 - 11 mph
4 - 13 mph
5 - 17 mph
6 - 19 mph (comfortable cadence in top gear)
7 - 24 mph (max)
You'll note that the bottom 4 speeds would be OK on a bike trail with good judgment. Not strictly legal in all areas, but if you're not being a jerk, you won't get bothered.
This morning before my commute to work, it was already 90°F and humid. I got to work with only a tiny bit of sweat, and not really from exertion. It's a nice option.
Another way to look at it is that you can pedal as if you're going 13 mph (a comfortable speed for me on flat ground on my Trek hybrid) but actually be going 20, and without needing a hardcore road bike.
The Trek Allant+ would do everything my Ranger would do except really soft surfaces like sand or snow.
In the heybike lineup, their Race model is more conventional and costs half as much as the Ranger. (They call it "Race" but it is really a hybrid style bike) heybike is a Chinese brand, but rather than going for bottom price, they actually have good customer support and that makes the bikes cost a couple hunge more than the super cheap, low quality ones.