I know there are several plots of vacant land in Denver and the surrounding areas.

You would pay the tax from you other money, effectively subsidizing your retirement indirectly.

My only real concern is the effect of a shut down of the fracking industry would have on Washington County specifically.

The repayment terms for a 401k participant loan are equal monthly/quarterly payments of principal and interest (typically prime plus 1%) over a 5 year term (longer if used to acquire your principal residence).Please note that if you take a full $50,000 and then pay back the loan, you can't take another $50,000 until 12 months after the first loan was fully paid back.Per the loan offset rules that went into effect with the 2018 Tax and Job Act: if you leave your job and the loan is current at the time you leave your job but then the loan goes into default because you left your job, you will have until your tax return deadline (including any timely filed extension) to make the loan current by depositing the outstanding balance into an IRA (and thereby avoid the taxes and penalties that would otherwise apply).Please keep in mind the multiple loan rules:Under those rules, the sum of the balances of a participant's outstanding 401k loans under a single 401k plan (using the highest outstanding balance of each loan over the last 12 months) can't exceed 50% or $50,000 whichever is less.

As a new investor I don't know how much effect the housing sales market and the rental markets effect each other. 

1) Paydown the principal of existing loan using heloc.2)Recast the current loan ( instead of refinancing) to lower monthly payments3) Start using heloc as q checking checking , since the rates are almost zero in a traditional checking account.This is just one cost effective way of reducing interest costs I can think of and it costs almost nothing without going through any closing costs.

Would it be more cost effective to convert a detached garage and build a new adu?

Looking for advise if anyone has any leads on cost effective skip tracers who use TLOxp.I used some fiver providers which were very cost effective, but definitely did not get TLO data (Despite claiming to).Any recommendations are highly appreciated.

Know the market price and simply let the tenants know that effective (date), the rent will increase to $xxxx which is consistent with current market rent. 

@Rod HanksWe terminated old lease and they signed my lease effective date of closing.