Pay yourself a "reasonable" salary on a W-2 and use a big chunk of that to contribute to a solo 401(k) (no other LLC employees except a spouse allowed) or a SEP IRA (other W-2 employees allowed) plan. 

A lot of forum members are very knowledgeable in their respective fields related to real estate investing, whether that is real estate sales, wholesaling, flipping, rentals, lending, self-directed IRA and Solo 401k investing, or tax and legal guidance.If you haven’t been to it already, you might want to check out the BP blog: https://www.biggerpockets.com/blog/The site has quite a few tools that can be helpful for new members.

From real estate sales, wholesaling, flipping, rentals, lending, self-directed IRA and Solo 401k investing, or tax and legal guidance, you will find that many members here are very knowledgeable in their respective fields.

If you can't roll it into a SD IRA, you may be able to borrow up to $50k from it and use that money without all the restrictions that come with SD-IRA funds.

The question was, what if I sold, used the sale to help put more money down on the primary residence, drop the mortgage and invest the difference in the market (401k, IRA, Traditional Brokerage Account).Duplex Numbers: Refi in 2021, 240k. 

One idea I had was to go to SD-IRA investor meetups and cultivate them myself.

My wife and I just hired a financial advisor (her idea) last year to set up IRA and college funds for the kids.

I'm a big fan of Roth contributions to start with for employer-sponsored retirement plans like 401(k) (and for Roth IRA, the "back door Roth IRA" method with initial non-deductible contributions to Traditional IRA and converting to Roth IRA). 

I have known about self direct IRA but not Self Directed 401K and 'Checkbook' IRAs.

A lot of forum members are very knowledgeable in their respective fields related to real estate investing, whether that is real estate sales, wholesaling, flipping, rentals, lending, self-directed IRA and Solo 401k investing, or tax and legal guidance.Discounts on some products and services are offered to BP members: https://www.biggerpockets.com/perks/proIf you haven’t been to it already, you might want to check out the BP blog: https://www.biggerpockets.com/renewsblog/The site has quite a few tools that can be helpful for new members.