First of all, welcome to the board, and to road riding. I started with mtb too, but now I'm hooked on the road bike.

If you have long legs and a short torso, I suggest you look into women specific bikes, like Trek's WSD models. Actually, Trek bikes tend to have short top tubes in general, so you might be comfortable on one of their non-WSD bikes as well.

When you're ready to buy a road bike, the shop should measure and fit you. This should involve, at the very least, measuring your height and your inseam length, both while barefoot and wearing bike shorts, as well as the width of your shoulders to determine the size of the handlebars. If the salesperson eyeballs you and suggests a size, or goes only by height, ask to be measured or consider going to another shop where they're willing to do that.

As for your saddle... I had similar problems and the saddle I found most comfortable was the WTB Rocket V Pro Gel. The center of the saddle has a "love channel", which is a part that is set a bit lower than the rest of the saddle, so it takes some pressure off the girlie bits. WTB has sells some neat "test ride" saddles to bike shops, which they can lend you for a few days so you can see if they work.

You can also try a cutout saddle, such as the Selle Italia Lady Gel Flow, which comes in several nice colors, or one of the Terry saddles that have cutouts. I personally do not like cutout saddles, but the only way to know if it works for you is by trying. Terry has a 30-day return policy, by the way.

As for handlebars... you'll really be missing out if you don't use drop bars. It only takes a bit of practice, and a bike that's the right size, so you can comfortably rest your hands on the hoods without feeling all stretched out. Also when you buy your bike, you can get them to put several spacers under the stem, and if in the future you want to go lower, you can have some of the spacers put above the stem so that you're in a lower, more aerodynamic position.

Good luck and have fun!

Cari