20 miles is a long commute. I would suggest you also have at least a couple of shorter rides that you can drive to and leave your car. There are many reasons for this including getting a late start, having to get home quicker for appointments etc etc etc.

Bimodal commuting will go a long way in keeping you motivated.

You will work out the eating thing as you progress. I would start with toast or cereal at first and maybe eat a good breakfast at your morning break.