It has to be exciting to plan such a ride! Take a look at https://www.crazyguyonabike.com
This is a great blog site where people who have toured write their stories and usually list equipment used. Also, The American cycling association (ACA) have excellent touring maps of cycling routes and bike paths. They are based out of missoula, Montana. I would recommend a 2 person tent. One that you can sit up in and store your gear in doors if it rains. Also, join "warm showers". This is a group that are bike and touring frioendly and allow you to shower at their homes and many will let you set your tent up. Fire stations are another great place to set your tent up. In terms of gear, most people who have toured realize tey brought too much stuff. There is a lesion there. Don't go cheap (walmart) on the gear....you get what you pay for. You also don't have to purchase the most expensive. Are you going to cook. There are plenty of Utube videos on building your own alcohol stove, or wood burner, Usually out of a pop can. Have fun planning. If you need a place to stay in SW Iowa, on highway 34, let me know.

Tom Young