Well, your off to a very good start with that weight reduction effort. I have a converted MG Midget that you can see at
www.electricmgmidget.com that has a 112 mile range and could be very similar to your build. I used 120 volts and 160AH batteries, so that is very close to your guess at what you'll need to get your required range. Be careful in picking the volts VS AH as that can change the way your car drives as far as acceleration. The total KWH will be more important to your range. I try to discuss my motor and battery trade offs at my site, so you will find that useful. I kept the transmision and clutch, which I highly recommend doing to get a good driving car. Please feel free to get in touch with me directly if you have questions. I'd be happy to help you in going through your design options.