From an avid cyclist that raced for about 15 years, and still logs about 2k miles a year (down from 6-7k), I think your best approach is to treat it like a tractor purchase.
When someone new is shopping for a tractor the common advice is to go in to the dealer, talk to them, tell them what you're looking for, and listen to their advice.
Same thing if you're shopping for a bike for the first time. You'll be surprised what a good bike shop can help you with. For example, the most important thing if just getting into cycling is to spend money on the parts where you contact the bike. A good seat and shorts, good pedals/shoes, and good handlebars/gloves. These are precisely the areas where cheap bikes will skimp. Saving a few extra pounds on the bike, or a motor that runs a little longer is meaningless if you're uncomfortable and miserable.
Just like a tractor, get on a bunch and ride them. There are about 10 different "kinds/models" of bikes that you will find for most major brands. They all serve a purpose, just like tractors, excavators, skid steers, etc. all serve a purpose.
Yes, you can get cheap bikes online, that will get you from point a to b, just like you can buy grey market tractors that will pull just as well.
Just as your relationship with a dealer can be crucial, if you aren't comfortable with the ins/outs of modern bikes, a good shop is equally critical for repairs, advice, etc. It's the difference between waking in with your bike and saying "I ran into this problem" and them saying "sure, let's take a look quick," (and then not charge you) versus "fill out a ticket and we'll call you in 2-3 weeks."
If you buy from a shop, you can also expect, at the least, a free 30 day tune up.
Margins on bikes, like tractors, are pretty low. The huge mark up is on the accessories. So, if you buy some gloves, shoes, and a helmet, water bottles, spare tubes, patch kit, saddle bag, water bottle holders, etc. at the time of purchase, you can also negotiate the price some.
I see you drive a John Deere. If you're looking for similar quality, dealer network, support, etc. I'd recommend sticking with Trek or Specialized. They are like the Kubota/John Deere of bikes. It's hard to go wrong. They will also be very competitively priced with all of the major (not off label) brands. That's not to say there aren't other good brands out there (Cannondale, Giant, etc.) but you're most likely to come across those two brands.
