I believe it is all cut and dry websites for $10/month.If you'd like your visitors to search for listings, you'll need to integrate an IDX I use iHomefinder or IDXBroker.

I would like to have a way of having visitors to the site (potential investors) fill out a questionnaire and then submit it, adding themselves to my buyers list and having an email service send out an email blast at selected times with selected properties.

We get mostly families and international visitors.

I'm in Waco, so probably closer to $90 to $100, but we have a lot of visitors (2nd most in the nation right now), so I'm sure I could swing $600 / mo in rentals and break even.2) Nothing extra required, but I would opt into Turo's $1M liability policy.  

I would suggest reaching out to a local Architect who is familiar with the zoning and is a frequent visitor of the zoning/planning board meetings.

Lake Winnipesaukee is a pretty neat area.First thing I would do is make the list broad and start to narrow it down based on cleaning crew availability, STR laws/restrictions and possible visitors.

It is the only laundromat in a town of 4000, with more summer from summer visitors to the nearby lakes and state park.

I also get visitors from local churches, and with ring or some other type of video, I can choose not to answer the door if no one else is home.

Which in turn has brought a GR8 deal of $ to the area in the way of visitors and quite often visitors after visiting fall in love with the quaint town and move here.  

See here:  https://wikitravel.org/en/New_Orleans/Central_CityNote where it says, "Although crime has gone down from mid-2009 to early-2012, Central City is still a dangerous neighborhood, not recommended for casual visitors.