In addition to the Trek 7000, this is what I am preparing to buy:

Topeak RX Trunk Bag DXP
Topeak Modula Cage Waterbottle Cage
Topeak QR BeamRack RX Bicycle Rack
Topeak Road Morph G Bike Pump with Gauge
Cat Eye Rear Bike Light/Flasher - TL-LD1100
Cateye HL-EL510 LED Bicycle Headlight
Giro Indicator Sport Bike Helmet

And a few carry on tools, tubes, patch.

Am I ready?

you might want to add cycling gloves (they really save your hands the first time you "eat pavement.) Depending on your climate... rain gear.

Sounds good to me! Do you have a lock? Even if you have indoor bike parking at home and at work, you may want to stop off on an errand on your way home. You can then figure out as you start commuting what other things you find would suit your own preferences. I like to ride with a mirror, others don't and just shoulder check periodically and as needed.

Summer is coming up. You may want to get some sun block, shades, a bandana for your forehead so the sweat doesn't get to your eyes, tire levers and a water bottle for your bottle cage.

Ready to me is more a mental state. Once you have the basics: spare tube, decent helmet, a pump, patch kit, lights and a lock it is just getting past the mental hurdles. Things like distance, rain, traffic can all throw you for a loop. Getting out and breaking those hurdles does a lot to instill confidence and keep you on the bike.

I will obviously be adding more as I go. As for the lock...right now my trip will be only 7 miles on the bike and almost 30 in the car. Plenty of time to stop for errands with the car. I can grab a lock when I start commuting farther. I was thinking about a mirror, but didn't add it to the list becuase I need to get the bike to check how and where I'll attach it. I think I'm going with bar end type. I'm going to try riding with my current shades and decide if I need a more wrap around type. Definitely the water bottle. And I was lumping levers in with the tools.

Good start?

I agree. If you ask people whether you have enough accessories, you'll end up getting a never-ending list of clothes and gizmos that various cyclists can't imagine their commute without. And each object might indeed prove indispensable for the person who's recommending it, but for you it may end up being a purely optional nice-to-have thing, or even something you dislike. For example, out of the list of suggested additions I personally would only go for sunblock: no need for shades, bandanas or gloves for me. Yet the people who recommended them probably really swear by these things. So start with the basics, and with time you'll figure out what else you might want, if anything.

Heck, when I started commuting, I had no guidance of this forum, and absolutely nothing other than a bike and a really dinky lock! Had no clue how to change a tire. No water cage or water bottle. No knowledge of cycling safety other than "stay on the sidewalk at all times". (Gosh, that poor guy pulling out of a driveway was REALLY shaken as I flew over the hood of his car...) You have actually done your research, and you'll be fine.

Sounds like you are ready. One last thing I will add is

Practice repairing/replacing tubes for when you get a flat. It looks easy but I found out that it makes it less stressful when you know what to expect from your tires. Meaning, how easy are they to remove and how easy are they to put back on.

Yep yep. You'll figure out what other stuff you want/need after you have been riding for a bit. Have fun.

Do you really have to go with the seat post rack? You'd be much happier with a full rack if you've got a place to attach it.

You might want fenders at some point, but that can probably wait.

If you plan to actually use the Cateye headlight (as opposed to having it for emergencies), I recommend getting two sets of rechargeable batteries and a good charger. The claimed battery life is really high, but it gets noticeably dimmer after about 4 hours. I keep one set of batteries in the light and another in the charger and switch them every couple of days.

So true! I used to ride my 15 mile r/t commute with enough stuff for a 300Km brevet when I first started out.

For my commute now (25-35 miles r/t depending on how I feel) I'm down to a handlebar bag with a couple tubes, my pump and levers, phone/wallet/ID badge for work, and a Topeak Survival Toolbox on my seat tube.

At this rate, 20 years from now I'm gonna be riding double centuries with no bags, a half full water bottle, and a stick of gum in my jersey pocket.

My sentiments exactly! REI has this rack too.
https://www.rei.com/product/697821

Since you're asking...

Full fenders.
Power Grips (unless you ride clipless.)
Headlights powerful enough to light the road in front of you.
Rear lights that can be seen conspicuously in broad daylight.
Comfortable spandex undergarments.
Personal lubricant.
Sue Bee honey packets for emergencies.

Exactly. You know what would make an interesting thread? Instead of "what do you carry/what do you need," how about "What did you get/once carry that you no longer ever use?"

Yes, gloves. I have only "made use" of my helmet once, but I've done major skin removal on my hands 3 times in my life. I will no longer ride without gloves; I'd almost sooner ride without a helmet. It's no fun having bare raw meat on the heel of your palm and keeping it dressed for 2 months while the skin grows back. NOT pleasant.

This is interesting. I wonder if different people fall different way. I've had my share of road rash, both as a kid trying to do crazy skids, and as an adult - but not once did I hurt my palms in the slightest. Nearly all the damage is to knees and elbows.

That's the same rack I have on my Trek 7000. It's excellent, and fits well.

Do your legs work? That's the key component.

I guess I should have given the thread a different title.

"Is this a good list of absolute BARE minimums?"

As for that rack...I believe it comes with side frames. So even if they aren't meant to attach, I'm sure I could figure something out.

The answer, of course, is "it depends". What's your commute like, and what's the "absolute BARE minimum" of stuff that you need to transport back and forth? For me, with my commute, a lock is necessary, a tube and pump are not (I commute in a city, public transit is always there if I have a flat, but if I have to stop I need to be able to lock my bike). I don't need a rack or trunk bag or panniers because I use a backpack, which is also what I use when I'm not on the bike -- one bag goes everywhere. So...it depends.

Starting with part ride/part drive and steadily increasing. 7 miles, 15 miles, 20 miles, 27 miles. I'll need to carry clothes for work, shoes, frsh towel. There will be NO public transit available as I'll be on mostly suburban roads. For now, of the total 35 miles, I'll be driving about 28 of them. So I can do any errands with the car and not need a lock right away.

The main issue is stability. Seat post racks can swing side to side and bounce. The side frames won't really help with that.

Yes! Just do it! You can always refine as you go. But if you haven't bought the rack yet and your bike has dropouts to accomodate (which it looks like it should) go for a non-seatpost type rack as they are much more stable.

After some of the responses, I am thinking I'll go with the Topeak MTX Bag and a non-seatpost rack. I like the Topeak system.

Good choice. Consider the Explorer MTX rack linked above (at REI), which will match the MTX bag.