Like Capt. Rick, I have lived in North Charleston and have had no issues. North Charleston often gets more of a bad rap than it should...sure there are places you can get into trouble, but by and large the areas you are talking about are OK.
Whitehall is a well established neighborhood, most homes in there are over 10 years old, but nice. They have amenities (pool, tennis courts, playground, etc.) that you can use.
Charleston Park is new, last couple of years, but it's been awhile since I've gone through there. I think they had some walking trails. I also think the development may have slowed down due to the economy, but I don't recall. I don't know if they have any amenities.
I know nothing about Indigo Palms.
Don't leave the various subdivisions in Wescott Plantation out of your search. Wescott is on the North Charleston municipal golf course and has a pool and other amenities as well.
Also, Taylor Plantation would meet your requirements...they have nice walking trails, but I think their Homeowner's Dues are pretty high.
In all cases, the popular Dorchester District II schools are currently undergoing line changes. The new elementary lines can be seen on the
website, the High School lines will be unveiled tonight at Fort Dorchester High.
**EDIT** the proposed High School lines can also be seen on the website now.