They tend to shift towards the midwest due to the cashflow and appreciation potential.

I've had this situation before and it can work out well when you and the tenant agree to a payment plan, especially when the funds can come out of their account automatically.  

I'm a bartender, so I could increase my budget by picking up a few extra shifts a month, but this will cost time. 

If you have extra taxes then you should absolutely account for them.Contact Vrbo, Airbnb and your local authority and see if they are automatically taken out or if you need to submit the extra taxes.

It also allows tenants to set up automatic rent payments, so no more late rents!

Anyone shifted gear from STR to LTR ?

Most couldn't even manage a shift at McDonald's or Walmart. 

Lastly, should I continue collecting rent through Venmo or should I have her set up automatic payments with my bank? 

Because of bedroom sizes and the septic system's limitations, we limit it to two total.You are not automatically violating Fair Housing by limiting (or increasing) occupancy standards.

In Delaware a lease automatically rolls to a month to month lease if no renewal is signed and 60 day notice is required to vacate (or to give notice to move)  If you prefer to have it vacant in the summer then give her notice to move and not leave it to chance.