Trek Navigator 7 speed , one option hybrid hub rear ,internal gear 3 speed +a cassette .. Sachs made a 3 by 7 (
SRAM bought out Sachs , but they dropped the Dual Drive.. this year..
Sturmey Archer still offers a version of that.. new rear wheel..
Other option New Efneo GTRO, a 3 speed planetary gear crank , no derailleur, so it will shift stopped. or at any speed
a 28t low, + overdrive to act like a 40 or 50t,,& Patterson Metro is a 2 speed 28t , + a 45t in overdrive..
chainring through gear box turns faster than the crankarms.
the way slack seat tube on your comfort bike is not the easiest thing to put a triple chainset & FD on ,
so these are ways to get around that..
.....