We stayed at Dolphins Cove in October and there is no way I would walk that. I would take ART for sure. One of the things I liked about ART is during lunch instead of eating at the parks we would hop on ART and one of its stops is right in front of Red Robin. We could eat lunch there where things are a little quieter and less hectic and then either go back to the hotel for a rest or back to the park. This saved us money, we got better food IMO and it allowed our family a break.
ART pickup is right around the corner from Dolphins Cove, just past the Dennys. 5 Minute walk at most.
I really like Dolphins Cove also. We have stayed there 4 times now and its easily my first choice, they are starting to put in split systems in the units which will make the air conditioning much much better if needed, plus the gates community is really nice and safe feeling as well. Nice pool and a fun little mini golf course on site that is free as well.
The park has been super packed for awhile now and the break is really nice.
Hope you have a great time!