Hello experts,  I need some help here since I couldnt really find good answers online. I made a purchase of a lot with a duplex in OR which according to the city I can have 4 units in total. There's an empty land next to the duplex and I already hired a landsurveyer to draw the lot boundary with marking on the ground. I'm hoping to build another duplex on that land. and I'd like to put a nice trailer as an airbnb place while I gather the money or do the pre-work of building the duplex.  Here are the parts I need help...

- Who are the people I need to contact to get things going?  I already have the site-map but I believe I need to get the land prepared and planned for my goal.  I dont know whom I need to work with to get there...

- The empty land doesnt really have direct road access.  there's a tree in the middle.  Who should I find in that case to build an access road to the land?  without that, I probably cannot even get the trailer on the land

Thanks for reading and the help in advance. 

For the First I would start by talking with a couple local builders, and see if you can get a ball park of what it will cost to develop the land, I.e. grading, bringing electric out, and water, if not already there. They can also help with setting up the proper permitting and approval for putting a "driveway" in from the nearest road. You could go to the city and file the paperwork yourself for the driveway and contract it out with a paving company to get around the upcharge for the General Contractor. 

thanks Tim.  in this case...would it be better to talk directly to a builder or an architect to start?  I'm not going to for any fancy design as im going to rent it out.

@Charlton Ho , it depends on how hands on you want to be.   Builder will be a great one stop shop who will likely be able to handle everything, as Timothy noted.  But they will also up-charge for everything, which very well could make the whole project cost prohibitive.

If you are willing to put in a lot of work, you might be able to tackle this on your own, and hire subs directly, but again there is A LOT of work, and being a novice, it is likely you will make some costly mistakes.  If you want to go this route, I would start with a call to the building department.  They have always been very helpful with me.  From there, it will likely be an architect to get plans and constuction drawings, then onto a lot of calls to find site work, plumbers, electricians, foundation, framers, roofers, carpenters, windows and siding, gutters, drywallers, cabinets and counter, flooring, etc.

Thanks Evan.  this is helpful to know.  I'll try that!

@Charlton Ho you need to start with an architect. They start with code, compliance, and drawings. You really can’t even talk to a builder except to get very general numbers before you have consulted with an architect.