Re: Thinking about a M-Bike in E NC
I think your Schwinn cruiser is a good choice in the bikes available at Walmart and in your price range. The seven speed would permit you to assist the motor some on a stiff incline. A 2.125 tire gives a nice ride. You will want to beef up the fender supports to keep it safe, but that's what we're here for, to advise as well as we can. I also think it's cool that your wife is interested. Riding together could be a great thing. For her I'd suggest a 24" cruiser in a man's bike with a cantilever frame. Should have plenty of room for the engine even with the smaller frame (but measure first before you buy, of course), she also would have multi speeds for pedal assist and the 2.125 tires for comfortable riding. I'm guessing that cruising along at 20mph or so, having fun together and arriving at the beach without a sweat is more important to you than how fast you can go. Sounds like a fun thing to me. Welcome to the forum.
Someday when I grow up I will probably lose interest in toys with wheels, but until then...