Is there a good authority website that allows you to properly estimate appreciation over say, a 5 year period in a specific zip code? 

The setback information is likely published online at the jurisdiction's website.  

It is a good website that has a lot to offer you.  

I haven't found many investors from the area on BP, but if you know of any landlords in the area you could try to see if they have a website or find their contact info.Depending on the type of rental properties you want, you might consider meeting with the many apartment owners in Mt Pleasant to pick their brain.

I have had great success utilizing the same websites. 

I also use a website called UECONOMICS, but I would love to find a mobile app that updates regularly. 

Glad you joined the best real estate investing website!

I poked around the website and it is possible to be a vendor to the agency, but part of me is a little leery about registering with the gov't.

I am going to self manage & I have a couple other quick questions :I would like to set up for my tenants to only be able to pay their rent online, which website do you recommend for easy of use, efficiency for tax reporting & is the best for the cost of use? 

I spend a few hours on the property appraiser website each day and I believe it's the first time I have seen this.