I use Redfin and cyberhomes.com. I also use foreclosure.com but do not subscribe. I am looking in a very small area where I am familiar with most of the homes, so I can usually figure out which ones are listed on foreclosure.com There are a lot of knowledgeable realtors on Piggington: SDRealtor and sdrealtor to name a couple. There are also people who specialize in the areas you are interested in who will probably post when they see your question.
There have been a lot of postings on checking into HOA’s. Use the search bar at the top right corner and run a search on HOA for a listing under that topic. Good luck.