Hi Tony,
I'm so excited to answer your question as one grandparent to another. We brought our five year old grandson several times this past year, and had a blast. We spent an entire day at the Magic Kingdom and rode rides that we had not done in years, including Dumbo the Flying Elephant. We almost forgot how much fun it was to be at the Walt Disney World Resort with little ones. You are going to have the time of your life!
You have chosen an excellent time of year for your trip. You can't go wrong with any of the weeks between late October and early November. If you'd like to spend some Trick or Treat fun with your grandson, you may want to schedule your trip around
Mickey's Not So Scary Halloween Party which
runs on select dates in September through October 31st. The dates have not yet been announced for 2015, but stay tuned to the Disney Parks Blog for additional announcements about this year's event.
My top recommendation for a deluxe resort would have to be Disney's Yacht Club Resort or Disney's Beach Club Resort for one spectacular reason...Stormalong Bay. (see video) This three acre water park has tons of wet and wild fun for both kids and adults alike. After you have spent a day in the sun, head on over to Beaches and Cream Soda Shop for some cool ice cream sundaes to finish your day.
In addition to all the amenities at the resorts, you are within walking distance to Epcot and Disney's Hollywood Studios. Boat transportation is also available to these Theme Parks in case you need to rest some tired little grandson legs. (and maybe some old legs, too)
Have a great time making magical memories with the next generation!
Leanne T