Sounds amazing! I've not built new, just a recent whole house renovation. I'd start sketching out the floor plan with graph paper. If you haven't started a pinterest board for each room and each finish/feature, that would be a good place to organize your inspirational looks.

You will want to find an architect to draw up plans for you. I'd research online first to get some ideas of what style home you want, approx. square footage, one story or two stories, and general floor plan. Try http://www.architecturaldesigns.com/--they have a lot of house plans to search through. Once you find a plan, have an architect draw them up (or purchase online if you find one you don't want to make changes to). Then take your floor plan to several different builders for them to price a build cost for you. If you know what type of finishes you want, make sure you write them down for the builders to incorporate into their cost analysis. Share your Houzz and Pinterest boards with the builders so they can see what style of home and finishes you want. Good luck!

If this is to be your forever home, spend some time researching efficient house design. It pays to understand all of this stuff so you will know if your architect and builder have a clue how to properly build an energy-efficient home. There have been tremendous strides in building quality and efficiency, and building codes (in some areas) have been changing a lot in recent years. I cringe when I drive by brand new McMansions being slapped together out of 2X4's the same old way, resulting in the same old sky-high energy bills.

There are some good sites catering to this information, such as buildingscience.com, and greenbuildingtalk.com. There's a lot to it, starting with siting the home on the land, and going on through various design factors, and proper selection (and installation) of building materials, doors, windows, and HVAC equipment. Considering the cost and life-span of a house, I think it's worth putting some time into getting it right.

It's not just about saving money, since it will cost you some extra to get a high-performance house. A well built and designed house will be a lot more comfortable to live in, without cold spots and drafts. An energy-efficient home is also better for the planet, if that's important to you.

An architect can help you translate your vision and lifestyle needs into a set of plans and specifications for your home, barn, and boathouse. What they typically don't do well is accurately estimate the construction cost. To be fair, their day job doesn't involve building, purchasing materials or hiring subcontractors so it would be pretty hard for them to maintain any cost estimating expertise.

If keeping to a particular budget and timetable are important to you, then I encourage you to pre-select both your architect and builder and have them collaborate with you from the outset. You could also choose a design/build company that can take you from concept to completion with a staff that works under the same roof.

Regarding stock plans available for purchase on the internet, please be aware that they are copyrighted intellectual property. Copying them--even making whatever changes you have in mind-- is in violation of U.S. copyright laws and the penalties are significant if you get caught. If you find a stock plan that fits your needs, purchase them and then have someone make the changes to them.

Best wishes for a successful project.