You can get road bikes with flat bars. These are generally considered more urban bikes, and are less expensive than equivalent models with drop bars.

If you want to go on more gravel trails than just your first half-mile, you could consider a cyclocross bike. These are designed to do some amount of off-road for cyclocross racing; they also make good urban and long-distance bikes.

The Lemond pages are available by searching the Wayback machine; unfortunately the geometries were in pop-ups, which were not saved. Everything else is there, though. It was really annoying of Trek to pull the pages, when it is useful as an archive.

These are not hard and fast rules, but some typical set-ups:
Stand-over height: 0.5 - 1.5 inches, pulling into your pubic bone. If the top tube is sloped, standover in the middle. This will give you an idea if you are on an appropriate frame. Bikes are measured from the center of the bottom bracket / pedal spindle to either the center tube or top tube of the seatpost (so first you need to figure out which measurement is being used). The bottom bracket height off the ground will also be different for different bike types and manufacturers. I ride a 52 cm Bianchi Volpe cyclocross frame; I was looking at a 52 cm Lemond Poprad (cyclocross), which ended up having a higher bottom bracket, so it was more equivalent to a 54cm bike in most models. Basically, you will fit a range of sizes - mine is about 51-54 cm. Your height doesn't have much to do with it, your leg length does - I am 5'6.5".

Seat height:
* 0.833 x your inseam, measured from bottom bracket to lowest part of saddle. Measure inseam by standing with feet 10" apart, pull a book or T-square held against a wall as hard as you can into your pubic bone, preferably wearing the same clothes you will use for biking.
* Put on the shoes you will use with bike. Put your heels on the pedals and adjust until legs are straight. When you use the ball of your foot, your leg should be bent about 20 degrees.
* Set the seat as high as you can without rocking side to side. Have someone behind you check this.

Saddle position on rails:
* Most people use knee over pedal spindle (KOPS) -- this was thought to be the position that generated the most power, but it actually differs for most people. It should get you in the right ballpark for trying out the bike though.
* KOPS: Level your pedals at 3 o'clock and 9 o'clock, parallel to the ground. Have a friend hold a plumb bob / metal nut tied to a string under your patella, the bony part of your knee. The metal "bob" should hit the pedal spindle.
* Changing the saddle position also changes the height. You will need to iterate on your own bike, it should be close enough for a trial ride you don't need to fiddle with it more.

Reach to bars:
**This is the most important part of fitting!** If the reach is not comfortable, the bike is not right for you. Again, reach varies by manufacturer for a particular height. Try out men's bikes as well, especially if you have long arms. The reach in women's bikes is too short for me; Bianchi has a slightly shorter top tube than average, so I ride a Bianchi men's.
* This is also going to vary the most, depending on what you want to use the bike for, how flexible you are, core strength, etc. Basically you want no more than 40% of your body weight on the front wheel, and you want to use your arms for support as little as possible.
* You should at least be able to hold the top of the bar (parallel to the stem), take your hands off, and not fall forward. Holding onto the drops and not moving forward is even better. This also depends on core strength though, which you can build up.
* A popular measure is having the headset on top of the stem obscuring the hub of the wheel.
* With your hands forward in the drops, your elbows should be about 90 degrees.
* Your arms and body should be about 90 degrees with your hands on the hoods.
* You can change the reach and handlebar height slightly with the stem -- you can get a different length and rise. You can't change the length too much though, or you will change the steering and/or get pedal overlap with the wheel. The change in handlebar height will also be small (unless you are looking at buying new, before the head-tube is cut, or at bikes from the 90s or earlier that have quill stems which are adjustable).

Though, really the best way is to ride a lot of bikes and find the one that has the best feel... similar to trying out running shoes, but for bikes you have to go to a lot of different bike shops to try all the models. This is what I did -- and the Bianchi just felt the best. Now that I know more about bike fit, and using some of the metrics above as well as putting my measurements into "bike fit" sites, it just confirms that I found the right geometry for me, just by "feel." Also, don't feel bad about trying out new bikes at bike shops, even if you plan to buy used - you will also need a relationship with a good bike shop to get accessories, tune-ups, etc. This is where LBS make money... the profit margin on road bikes in particular is extremely small. While trying out bikes, you will also be trying to find the best LBS for you to work with in the future -- starting with bringing in your "new" used bike for its first tune-up! You can also usually get bike fittings at a LBS, about $50 for typical seat height, seat setback, and reach (stem) adjustments.