However, I’m also contemplating learning the flipping business, either by working with a flipper or trying it myself, to generate a larger cash position.I’m open to the idea of out-of-state investing but would approach it conservatively.

Currently, I am planning to build single-family homes on those lots.Keep this business simple and focused on your niche.

Any 'investment' can act as a 'retirement'.Roth is great because it is tax freeI personally like real estate also becuase your cash flow is normally shielded by depreciation.I like real estate further because there is less complixities / restrictions when it comes to IRA such as the 5 year rule, year you have to take distributions, RMD, Unrelated Business Income Tax(UBIT).Your goal is to have the best return and the most money at the time of retirement, what is the best way to get there?

In the early stages, they will often email a business plan and/or hold a webinar describing the investment. 

Has anyone done business with this company?  

Quote from @Hieu Le: Most HOAs consider a short-term rental to be a business, not a residence.

The city will require a few pictures of the apartment to make sure it is live-able and once a lease is signed and submitted to HRA, they will verify the applicants income, and it will take up to 10 business days for NYC HRA to write a check for the total amount of the 1 year lease. 

I hope you and William can do some business together!

- Should I use my own capital up front or try to partner with an established land flipping business to fund the deals? 

Not a huge part of our business though.