Welcome! to bike riding and this forum. I haven't been at the forum all that long myself, but it is a lot of fun. Wonderful people and inspiration abound. I hope you can find..(make) more time to ride than I did when my kids were small. (teen and twenty now) Later years, we started bringing them along on big rides and made it our family activity. Consider getting your boys onto decent bikes ASAP, and teaching them to ride safe. I wish I had done this sooner. I also recommend running errands by bike when possible. Little rides in town - guilt free, don't usually take any longer than by car.

About the rack- unless you are tall, I recommend trying the rear mount rack. We have a roof rack and I hate the hassle of trying to get the bikes up there by myself.