If it was my money, I'd spend 700 on a dual suspended mountain bike. There are some manufacturers who make them so that you can mount racks and other stuff on them. You need the right bike so the friction drive unit can be mounted, preferably without too much modification. Friction drive is 250. That's a grand right there, with taxes. I prefer my bike to max out at 20 MPH, that way you don't need to worry about heavy gauge spokes and frame failure. Of course a decent mountain bike can handle more then a beach cruiser, out of the box. Whatever you decide, invest in some decent brakes. A coaster brake is not decent. Sturmey Archer makes a great drum brake. The great thing about this hobby, lifestyle, pursuit or whatever it is to you is there are so many ways to scratch the itch. I like to pedal so I lowered the gearing and always pedal from a stop before engaging the throttle. Some prefer to not pedal at all. Whatever you decide, it's all good.