If you have not yet decided on which of the parks to visit you might want to check 2 sites to learn the park hours and expected crowds for the dates that you will be there.
http://www.wdwinfo.com/ is the home page of the disboards where you can find park hours etc.
http://www.touringplans.com/tp2/UG2_index.php?PageID=0 gives advise regarding crowds. The next 30 days is free; for a full 365 day calendar you have to pay a fee to join.
When a park has Extra Magic Hours for guests staying on Disney property that particular park normally ends up being the busiest park for that day. That becomes most noticible towards noon.
Although Animal Kingdom is my favorite park you should be warned that on hot days it will normally be hottest in AK - by about 5 to 10 degrees. If it is not too hot when you visit remember that they do close earlier than any other park.
When we go without kids in December we only go to Magic Kingdom for the parades, Spectromagic, decorations & fireworks. We've done the rides enough times with kids to have our fill of them. But MK does have 3 coasters. Since you'll be w/o children you can head straight to Space Mountain (skipping the mad rush of strollers to Dumbo), then cross the park to Big Thunder Mountain RR & Splash Mountain. Grab a fast pass for Splash M to go again later when you'll need it to cool off.
After you choose your parks based on the calendar info. start working on a touring plan if you will be there during a crowded time.
Many people feel that Illuminations, shown nightly in EPCOT, is the best fireworks show.
Fantasmic, the show with fireworks at DHS, is only shown on select nights now. Check the schedule if you want to include a day at DHS. And then check the disboards for advise on how to get seating for that one. If there are thunder storms in the area the show will be cancelled and only the preloaded fireworks will be set off for a few minutes. The fireworks at MK & EPCOT go off every night regardless of weather but Tinkerbelle flies (MK) only when conditions are right.
