There are many health and nutrition sources available in print and on the web. Frequently the plans are designed for specific activities, though, oddly if you look closely enough you'll find they vary very little. Personally, I have found Bill Phillip's plan (
http://www.ediets.com/diet/bill/ ) to be very effective for me. When I started with it I was overweight and constantly feeling like I was dragging. I've been on his plan for about 4-5 years now and it has only cost me 40 pounds and a feeling of having enough energy to make it through the day and then some.
I have also found that while riding the portions and frequency of eating meals does not have to change. You may have to supplement more frequent snacking, but if you focus on healthy choices for this you can easily meet your body's needs.
The biggest stumbling block for me was all mental. When I started I looked at the portions and said to my wife, "Honey, I have to live, this is not enough..." It took about 2-3 weeks to adjust fully. Of course, once you are totally in the plan and reaping its rewards you save enormous chunks of change. I don't really eat out in many places since they bring a day's worth of food on one plate and expect me to eat it all in one go!
Lastly, welcome back! It's always encouraging to hear a story of someone either deciding to take up riding or getting back into it. Enjoy the ride!
P.S.
Where in Wisconsin? I grew up outside Milwaukee and miss it terribly. I keep an "Escape to Wisconsin" bumper sticker on my desk...