If you're self-employed, the Solo 401k plan will likely work better for you.A few Solo 401k benefits: Compared to an IRA, Solo 401k contributions limits are roughly ten times higher.There is no custodial requirement for the 401k.The Solo 401k can allow you to borrow funds from the plan, unlike with IRAsYou don't need the additional expense and administration of an LLC to have checkbook control.There is a built in-Roth component whereas IRAs are either traditional or Roth, not both.A spouse can also participate in the same Solo 401k plan.The Solo 401k has additional tax benefits over an IRA when investing into real estate using leverage.

@Dmitriy Fomichenko in regards to 'converting' traditional funds over that are already in my SOLO401K to the ROTH component, if those 'funds' are say a rental that I paid 100K for, do I need to get an official appraisal of that property to covert things?

The third component that makes a good deal FOR ME is the potential for appreciation, both forced and organic.

Generally, an inspector doesn't show up unannounced, with an appointment, for an inapplicable trade or component of a house. 

The two common choices for doing so are the self-directed IRA and the Solo 401k.The Solo 401k requires self-employment activity, but will allow you to take participant loans while the IRA does not.A few other Solo 401k benefits:Compared to an IRA, Solo 401k contributions limits are roughly ten times higher.There is no custodial requirement for the 401k.You don't need the additional expense and administration of an LLC to have checkbook control.There is a built in-Roth component whereas IRAs are either traditional or Roth, not both.A spouse can also participate in the same Solo 401k plan.The Solo 401k has additional tax benefits over an IRA when investing into real estate using leverage.The penalties for prohibited transactions are less severe, though it's best not to utilize this benefit :)With either structure, it's generally recommended that you do not commingle retirement and non-retirement assets.

Although there are a few extra components, seller financing to me feels more fulfilling.

All components rotted with worn finish .Unknown foundation status , with uprights set on blocks and wood.

Just because a property is 100 years old does not mean the components are 100 years old. 

There are a lot of moving components here, possibly too many. 

Compared to an IRA, Solo 401k contribution limits are roughly ten times higher.The Solo 401k will allow you to take participant loans while the IRA does notThere is no custodial requirement for the 401k.You don't need the additional expense and administration of an LLC to have checkbook control.There is a built in-Roth component whereas IRAs are either traditional or Roth, not both.A spouse can also participate in the same Solo 401k plan.