Southern Dunes as the name suggests are located south of the attractions, I am sure the villas are very nice but personally don't like the location.
If you are planning regular trips to the parks I would suggest staying in a different area.
My cousin used to have a house there. The area which is Haines city is quite quiet and small but there is a walmart exactly opposite the entrance to the community.
The house itself was nice and roomy, and there is a shared pool in the middle of the complex if your place doesn't have one
we stayed there last year and we found it fantastic value for money!
i was really impressed witht he villa and the journey to the parks wasn't too bad (about 30mins) when we timed it, if you dont book a disney hotel you cant expect to be right on the doorstep of the magic!
the walmart outside was great, along with a few fast food places like popeyes, mcdonalds and another few accross the main US27, a couple of 'dollar' stores which were great for the kids to spend some 'pennies'!
it didn't take too long to get to Kissimmee, on the 192 (where we spent a lot of time in the evenings.... good for meals and also the old town.
if you dont mind driving (which neither of us did then it is a great location.... in my opinion!
I've stayed there 2 times now and the villas are very nice and the estate is lovely along with the location of walmart and fast food places right outside the main entrance, however my problem is the same as others that the distance to the main orlando attractions can get a bit tiresome after the first few days, I would estimate around 30-35 mins to disney/192 and 40-45 mins to universal/I-Drive so if you plan on going to the parks and then back home for a swim/change of clothes then back out to I-Drive/192 for a meal you could be looking at at least 2 hours driving in a day (plus the additional petrol costs)
We stayed there in 2005, great area but just too far if you're doing the parks.
Not an ideal place to stay on your first Florida hol but it was allocated on arrival, never do that again!