Problem is, outside of vague mentions of Real Estate and other vehicles, it doesn't really delve into other investment options.I'm putting 8% into a 401k through my 9-5 (100% up to 4%, 50% from 5-8%), and I'm an accidental landlord (thin cash flow at the moment).

i had to provide car titles to all the vehicles i owned and prove that they were insured. 

I want to build more precise worksheets so I can have a better idea of the true cash flow in the future.

I just had my son born and am thinking of pursuing REI as the vehicle to freedom. 

I tend to believe this is akin to robbing your future self.As @Brett Laycock mentioned, an SDIRA is essentially a vehicle to own property through the IRA, and in this regard, the IRA makes money and takes the risk for itself... or for that future person, rather.Beyond that, taking money out of your IRA should be a last resort.

The latter is an argument as to why people continue to work beyond "retirement".The rest of the book doesn't have much to do with real estate - mostly stocks and other investment vehicles, and A LOT of mutual fund bashing!

I would call that middle class at least, and that's assuming 0% interest on that initial $3.5M.So, you're ***-u-me-ing perfect health, no injuries / accidents, no natural catastrophes (hurricanes / cyclones, wild fires, volcanic eruptions, ... at least two of which are common in HI), vehicles which last forever and never need to be replaced, destruction-proof housing and furnishings, ...... and if you CAN live that lifestyle in HI on $100K / yr (most people can't in ANY state), why are you not teaching personal finance at the university level? 

Check these:Department of Motor Vehicles - A trip to DMV will obviously eliminate the wait on hold.County Tax Assessor's officeDepartment of TransportationDepartment of Housing and Community Affairs/DevelopmentManufactured Housing DivisionOne or more of those can tell you exactly what's needed in your state.Good luck and have fun!

The location and the potential work/studio or vehicle storage space I believe would add to that number. 

Ultimately, if your wife doesn't come around then I'd suggest finding a vehicle you can both get into.