Incorporating a washer-dryer hookup in the main house could be advantageous.This addition not only increases the convenience for potential renters but also adds value to the property itself.

My goal is to live in the home during the winters, maybe 3-4 additional weeks for vacation, then rent it out to help cover the mortgage the rest of the year.  

And if still in Spain, how long until it's in US and is shipping additional or is price landed? 

Additionally, it's a good idea to connect with a Property Manager early on.

Give her 30 days notice now, keep her security deposit, and send her a additional bill for damages to the unit in lieu of taking her to court for the damages.  

Also, be sure to check with the section 8 agency managing the tenants - sometimes if you pass on an additional cost like that they will no longer be eligible to live there if the rent and utilities exceed what they were approved for.

Use extended closing periods or additional earnest to buy more time for your old property to sell if you need.The last option is what's called a reverse exchange.

Close to a cool little town, close to an area attraction, etc....Also do a search here and see how to screen guests, in addition to what the hosting sites do.... like no last minute bookings, no short stays....

I have a large lump sum saved in an investment account for down-payment and any additional costs.

Both properties have a substantial amount of equity that’s essentially sitting idle.Would it be a good idea to tap into this equity (through a HELOC, cash-out refinance, etc.) to fund future fix-and-flip projects or purchase additional rental properties?