There is no type of Disney trip I dont like, HOWEVER, traveling with only adults is freakin killer! I've been with my now husband once, my entire adult family and also went for my bachelorette party with all my girlfriends and have had the time of my life each time!
Go on and get up early and get to the parks. Theres nothing like being there before it gets mobbed, and the weather is a little cooler and nicer (its awesome to have that first cup of coffee as you walk around main street). Plan and book reservations at your fav restaurants so you can take a nice break, grab a beer or glass of champs (after all, you are in Disney - why not celebrate) and then get back to it. (MK - Be our Guest or Tonys Town Square for our outdoor table mid afternoon so you can have your meal while you watch the parade : Hollywood Studios - Sci Fi Drive in or 50s Prime time (both have a nice selection of beverages) : Epcot - anywhere really but the San Angel inn ALWAYS great food and Marrakesh with the belly dancers are awesome : Animal Kingdom - Yak and Yeti (these are always safe bets with great atmosphere)
On your Animal Kingdom day we always go back to Epcot for more food and drinks or Disney Springs for the same (Maybe even some live music or a drink on the water!)
Magic Kingdom - stay late and ride the coasters at night - so fun! (If you can, Be our Guest serves adult bevs only at night - hard to get reservations though)
Take your time in Hollywood Studios and just enjoy the day - to me this is the most adult theme park and I always have the best time with friends here. Second is Epcot (adult wise) esp if you are there during food and wine festival
Look into the Live music at HOB in Disney Springs - could be a super fun night out after a day at a park! - or dinner drinks and bowling at Splitsville in DS
I hope yall have a blast!