You can bank a TON of money for retirement (way more than a Roth IRA), and you can use it to invest in real estate. 

I will likely keep it as a rental in my ROTH IRA. 

Generally Id say invest into a roth IRA as soon as you can if you're thinking about the future.

One of our capital sources are smaller investors and people with money in IRAs that don't have the systems in place, the deal flow, or the underwriting expertise to run a portfolio.

The IRA LLC would probably have to pay cash for the entire project as financing construction in an IRA would be unlikely.

This is especially true if you are using IRA/401k.There is only handful number of lenders who specialize in non-recourse financing for retirement plans.

Do you also have a Roth IRA?

I also max out my ROTH IRA contributions, as well as what I have for a version of 401K for my wife and I.What tools / resources would you recommend to help me in the decision to continue to invest as I have - letting the REI support itself and max out IRA/401K, or stop those IRA/401K contributions and use them for 1 of 2 things (or both):  1. 

The CPA really has no good advice besides home office deductions and IRA contributions.  

Any ideas if a motivated seller having such an old apartment would be interested in accepting a low offer like this and if it still makes sense for me.Also, 1 last question, can i use a self directed IRA for a buying such an apartment and how does it work.