Since we will not have the time to actively pursue real estate investments  during this period, what are tips on staying engaged in the market and ready to roll once he returns home?

Has anyone felt the effects of regulations in those states?

I'm exploring my financing options and trying to decide the most cost-effective way of purchasing it.

Saying something to the effect of, "but it should be a quick form and might only take you 15 minutes

Forgive my saltiness, but its interesting that you don't even consider the effect this kind of disruptive spam marketing has on the end users, you say it "sucks" but only because YOU get called! 

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.

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.

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.

I also read that once the property goes from primary residence to investment HARPTA comes into effect.

If this were effecting your ability to lease other units, then you have a different situation, but if this is a single family home, or not effecting other tenants in the building, let it ride and count your cash each month.