We ended up going when my daughter was 2.5 months old. It wasn't ideal, but it was an extended family vacation so I felt I had to go. It turned out to be easy with her except for the long car ride there. (It's 7 hours without kids for us, 9 hours with kids and reasonable stops - it took us 15 hours to get back!) We're going back in less than 2 weeks and she's 8 months old, so I guess it wasn't too bad! We went when it was hot the first time. Though the baby did fine, I wouldn't recommend that. Baby gear really isn't an issue for us. Though we do use diapers and wipes, I breastfeed, co-sleep, and use a sling. I highly recommend a sling. That way you don't have to bring a stroller. We did take a stroller in case my daughter needed it but she was fine in the sling. My 3 year old used the stroller instead. Carseats are going to be an issue for years and years, whether baby is 6 months or 4 years old. At 6 months, there's a chance she might be small enough for an infant carrier - which is much easier to lug than those big convertible seats.
So, my suggestions are: Use a sling, keep the stroller at home if you have one. Get a crib at the hotel or rent from an area service if you don't co-sleep. Breastfeed. Buy a diaper bag that's a backpack - not just for your trip, but for all your needs! I used a regular diaper bag for my first child and a backpack when I had #2. I should have started with the backpack. Do not start solid food until after your trip. The current AAP reccomendation says to start solids at 6 months or later. Things will be much easier if you wait until you come back! The baby centers are great for distractable babies who don't want to nurse when there's too much going on.
I'm not sure what will happen with my daughter's napping this trip - she's the most distractable baby I've ever met and I usually lie down with her on her twin mattress to nurse her to sleep. At 2.5 months, she would fall asleep in the sling. A sling doesn't give the typical sleep position for a 6 month old, but it is next to mom and that counts for a lot at sleep time for my kids! However, if this is your only child, then you can always head back to the room mid-day for baby to nap.
*My son would have been a terror to take to Disney before 2.5 years old. Temperment definately means a lot.