Often times you can find a local architect or going on "Upwork" to find someone that can model out the addition you are looking for and get permit docs ready to submit to the city.Hope this helps!

Mini-splits would be a good choice here (no ducting required).Call an architect, they'll come out and look and give you ideas....

I use the system for two of my sites, my tennis partners site and also for my albuquerque architect site.

One of the most prominent reasons for failure is fear of looking foolish.

But to everyone else I call it a flip and call myself a house flipper or an investor if I don't want to get hit up about their "extensive" knowledge from watching HGTV and how I should partner with them and they'll just pick out colors for half the profit (this excludes my architect buddy on here who I would partner with and let pick out colors for a share, lol!). 

@Kyle Bentz I have worked with both of these contractors and find them to be pretty good.http://www.sierraconstruction.com/http://www.azzarellibuilders.com/if you need an architect for lay out or land use, Joe Belluccia is pretty good.http://www.jvbarch.com/index.htm

I would recommend you network with developers, architects, and contractors that have done the type and size of development you're interested in in your area.  

The house has a really nice floor plan that I spent a lot of time drawing with an architect, and I'm really happy with the way it turned out.

@Laura Thorne  When I was in school, my professor ,who was a practicing architect told me" if a client isn't willing to talk about budget up front, you should end the conversation shortly thereafter."

The AIA (American Institute of Architects) has lots of good examples of contracts.