Ouch. Lots of variables.
If money allows it, I'd start with a complete set of NEW tires, a sport touring type. If your current tires have some life left, save them, and slap them back on when the new ones wear out. Not real cost effective, but sure beats hunting tires on the road....and paying outrageous prices for a tire model you don't really want.
Newer tires will be a little less 'flat prone', also.
Chicago to the Rockies will be real boring!!
I've done it too many times. MAYBE if you haven't traveled much, it will be interesting. Maybe....
If it were me, and I had the resources, I'd trailer to Colorado, and ride the rest of the way. Don't know if you have a trailer....or if we can find a friendly person on the board in Colo to allow you to leave a trlr and car with for a week. There a couple of campgrounds in COLO that will let you park trailers for a fee while you ride.
It will be hot!
Carry water, drink a lot of it.
Once you're at some elevation, it will be cool to COLD at night.
You'll need to carry a variety of gear to keep you warm, dry, and cool.
Don't forget raingear!
Standard disclaimer on planning long rides......
If you haven't done MULTIPLE days of long miles on a bike, you're in for a shock! Maybe you've done a 500 mile day locally, once.
Once you string a couple of these together, the pain, strain, and discomfort accumulates, and becomes less tolerable.
Don't plan 'max' days for every day.
A lot depends on how old, creaky, or insane you are.
Younger, (Crazier) people can probably put up with high miles every day. The bodies can take it....
Personally, I don't plan for over 350 miles a day, overall.
That gives you time to visit some cool stuff you pass, stretch...commune with the locals, etc.
You can do a 'blast' to escape your local environs by doing a 'big' day the first day, but adjust your miles down after that.
If you aren't enjoying it......is is worth it?
How many times are you going to pass that way again?
will you get a chance to visit the WORLDS ONLY BOTTLE CAP MUSEUM, again? (Or whatever odddity you see a sign for....)
Even though you are becoming a LAWYER, most of us wish you no harm. Be careful!
Iowa and Nebraska are pretty boring, and will quickly flatten out your tires. You're looking at 900-1000 miles of riding before it becomes interesting!
Are you motel hopping, or planning on carrying camping gear?
There are some wonderful campgrounds in colorado.
(I may be heading there in a week.)
I usually top off every 100 miles. This gives me a chance to stretch, and the leeway to go farther for gas if the prices are outrageous where you stop. The prices will vary. Don't cut it too close. Particularily in the sticks....it's possible to have no gas for 50 miles or so, and the gas that's available may not be cheap.
I'd pack a basic tire plug kit for emergencies, some means of reliable inflation, a tire gauge, some zip ties, quick j-b weld, duct tape.......and you're normal tool kit, augmented with stuff you normally use for regular maintenance.
I love riding in SW Colorado. If you have time to spend a couple of days there, I can point you out some roads.
Nevada, and other desert areas are going to be BRUTALLY hot during the day. If you break down, get in the shade if possible, drink water.
If you haven't been in the desert during the summer, it can be an eye opener, and fatal. It won't feel hot, but your sweat is evaporating quickly...and you're dehydrating.
Anyway....lots of stuff to cover, but I hope I haven't scared you off.
Some people love doing 1000 miles a day on bikes. SOme people dream of them. (I don't....)
I've driven tractor trailers for 20 years, and other commercial vehicles longer.....have almost 3,000,000 miles in the US.
I still find myself wanting to go back to the little places I passed I never got to stop at, or to head up that road that leads up to a park....or the mountains....or the worlds largest ball of used chewing gum.