From the experience of others, would a simple, personal LLC where I lend money on projects and report proceeds as income or short-term capital gains constitute a 'business' and make me eligible for a solo 401k?

I was able to gain valuable experience walking these properties and working with the construction team to estimate cost of rehab and see the entire process through, from rehab to actually packaging the property for sale to investors.

I'm looking forward to gaining knowledge.

It must be a true sale.Remember loans have nothing to do with your basis or gains.

In regard to your advice about the Realtor, well, I'm hoping that the mls access I would have, the elbow grease I would put in, the knowledge of real estate I would develop, the colleagues I would meet, the broker I would get able to easily get the advice of, and the percent or two in gain vs. paying a Realtor will make my decision a smart one.

If you inherited these properties you should have a stepped up basis wiping out past deferred gains if set up correctly.You could buy apartments or triple net investing.

Do I need to talk to bankers or appraisers to gain this knowledge?

I'm new to Bigger Pockets too and would love to gain some insight.

He also told me that he made more from his rentals than he did from the law firm.He still held the entire portfolio of properties when he passed at age 90, giving the properties to his relatives who continue to keep the properties and run the rentals, living off the income. 30-40 free and clear properties does provide a nice "side" income.The "stepped up basis" provides that the inherited property transfers basis at the value at the date of death, which makes all the capital gains unrealized during the owner's lifetime tax free.This attorney had the same portfolio for maybe 40+ years, he never bought any more property and never sold any of his rental properties.

So for example if you waited another year or two you really do not gain much with getting better dollars invested today with low interest rates and pricing.