If they improve on it, $9/month for a rental with ACH option looks very reasonable

ACH or credit card. 

@Lucas Laufenberg Automated clearing house (ACH Payments)... you can set this up with your financial institution... like how tenants pay their utilities through their online banking... when they add a payee instead of utilities or a cell phone bill they will search for your corporation and deposit money directly into your account monthly... 

If you have gone through the permitting process in Denver, you know that brain ache is worth a couple grand.

@Mark DavidsonHere are considerations in choosing a Solo 401k provider and bank to provide the account:Solo 401k Bank Account Considerations:Here are some general considerations:If you want access to bank checks, a debit card and/or the ability to ACH funds out, you will need a bank, credit union etc. rather than a brokerage.There are 100s of banks and credit unions that have opened accounts for a Solo 401k.Keep in mind that the bank's role is limited to simply providing the account (i.e. no tax reporting, no recordkeeping, etc.) such you may wish to de-prioritize familiarity with Solo 401k plans and focus on other things that are important to you (i.e. branch locations, fees, etc.).If you want the ability to invest in stocks, mutual funds, etc., you will need a brokerage account.Many brokerage firms will open "free" accounts (i.e. no setup fee, no maintenance fee), which will also come with checkbook access and the ability to wire funds out such that they function as a "hybrid" between a bank and/or brokerage account.If you are looking for names of banks that open bank accounts for Solo 401k plans, there are many banks where we have received positive feedback including Wells Fargo, Bank of America, PNC along with local banks and credit unions just to name a few.

Zelle can work too since it's fast and free, but you'll need to police the late fees yourself if you go the Zelle/ACH/checks route.For tenant credit checks, there are a ton of options with very similar offerings at similar price points: MyRental, Zillow, SmartMove, and the aforementioned rent collection platforms, to name just a few.For automated bookkeeping and accounting, we have a solid platform at Stessa, and then there's also Quickbooks for more complicated entity accounting and Google Sheets if you don't mind the manual work required to keep it updated.Either way, there's no better way to learn the business than to self-manage, at least for a while in the beginning. 

Trust me when I tell you that in the world of science, medicine, engineering, probability...

What about the head ache part? 

As we say in the House of Medicine: See one.

Sometimes REST is the best medicine for the heart and mind.