I am having a house built, one of the main reasons I bought my Mavic Pro is to document the build and be able to easily see things without climbing a ladder.  Right now my house is framed up with a roof on, but the windows and doors are not installed, just big holes.

If I takeoff outside and attempt to fly into the interior of the house and back out again, what can I expect to happen?  What is the best way to approach this?  I was thinking tripod mode, because that automatically disables the vision sensors and slows down the inputs.  Also set the camera exposure to auto and auto focus.

I am worried that if it suddenly goes into ATTI mode while I am in tripod mode, I might not have enough stick movement to make corrections that I might need.  When windy, you can feel the draft in the house :-)

You can expect to block out gps, your aircraft will go to opti mode or Atti mode and if it goes to Atti mode it could drift.
If you want to document inside of your house I suggest buying Osmo mobile , you can then blend both videos get much better and safer footage.

You can also hand carry the drone through the house.  To make it flow properly, keep the elevation the same all the way through or make very smooth transitions so it  looks like you are flying the same stabilized bird.

Yeah you can also get a Cinema tray which holds the Mavic and would be easy to walk around and get shots.  Highly not recommended to fly inside.  Here is what I am talking about.  https://www.amazon.com/dp/B071DK ... ef_=lv_ov_lig_dp_it

Totally agree. Osmo would be an better option

Definitely an Osmo or Katana for safer results.

If you decide to put faith in your flying skills and try to fly inside, make sure you set to hover if connection with the controller is lost. I agree with previous comments and recommend the Polar Pro Katana tray for handheld recording inside.

Yeah, I'd like to get an Osmo 2 for sure.  But I have to think about the WAF...

Wouldn't it be a cool shot if I could start the video inside the house, say looking at the living room, then do a dronie and have it fly out the open front door?

one of the main reasons I bought my Mavic Pro is to document the build

Before they start putting on sheetrock or paneling.  Take detailed pictures with reference points to show where Electrical Wiring, Water Lines, Gas Lines, Waste Lines, Cable, Phone Wiring, Ethernet cabling, Alarm system wiring, and Air duct vents are located.  Put a large easy to read tape measure in picture to help with locating the aforementioned.

If there are any unusual studding, not on 16-inch centers, doubled up, or boxed in; document those too.

Having had to add Ethernet wiring, Phone lines, and Satellite Cabling, along with Alarm system wiring to two existing homes, I would have paid good money to know where several things ran, and to know about some strange placement of studs, and in one case three studs side by side.

Speaking of wiring, now is time to seriously consider running Ethernet and Alarm system wires.  Yes you can go wireless with both.  However Security cameras need power and decent Security panels need power.   

Before you put in your yard.  I would bury a couple of capped 1-1/2" dia PVC pipes going under sidewalks and drive way.  Makes adding sprinkler system, low-voltage lighting, and outside security cameras a whole lot easier.

You might test your drone, setting it inside in a few places to see if it gets a good GPS signal.

I know my handheld GPS receiver will pickup satellites inside the house.

In a one story house I had my Mavic Pro P in, it was picking up the GPS satellites.