1. Don't worry.

2. Pick a time to go. If you want low crowds, look at something like mousesavers best and worst times to go list. If you have to work it into your own tight schedule and can't pick a "good" time, just pick the time.
3. Either get a Disney TA to do it for you, or get on Disney's site and first see if there are any special offers covering your time (if you like to save money.)
4. If not going through the special offers link, just plug in your dates and info. Stay on site. Stay on site. Repeat: stay on site. (Okay, you don't have to, but I think you should do that.)
5. Pick some resort that looks nice.
6. Book trip.
7. Look at easywdw's calendar and pick ONE "green" (low crowd) park per day. Forget hoppers, btw, you can add them later if you need them.
8. Figure out what day is 180 days out from the first day of your trip. On that day, book a midday sit down meal at your chosen park. Or dinner. Or breakfast. Whatever. DO NOT LOOK BACK. Do not go back and check if your chosen day is still green. Just book the meal, and now you know which park you will be in on each day.
9. Maybe ... look at park highlights or read on DIS what is most popular so that you can get FP for something that really needs FP when you first arrive at the park (or book it early if Disney changes the whole way this works before you get there.) If you skip this, then after step 10, you just walk into your chosen daily park. Open your map (hopefully out of human traffic areas.) Pick some good looking ride and walk that direction.
10. 6 months later, go to WDW. Use the provided transportation to get around the place. Have fun, and don't worry about missing things. You will miss stuff. Who cares? Just have fun.
Whoops! Did I make it sound complicated?
Seriously, if you book a resort on property, it will make the trip easier. And just because everyone on the DIS has opinions about the best/worst resorts doesn't mean you have to stress over which one. Just pick one. Go. Have fun.
Don't worry about the details of transportation around WDW (to/from resort & parks). Once you are there it will be obvious. Big signs. Helpful CMs to ask.