The biggest key is getting either a contractor or flipper in your area who has done it in the past.

The key to gaining their attention is to spend some time learning and come prepared with well-thought out questions.Specialization is critical in commercial real estate.

Any advice on where to source inexpensive materials for general renovations?

Jason, with Ryson real estate would be a good source for info.

The key event in the foreclosure process is the auction. 

I wouldn't want to fully finance a turn key property here but would rather buy with 30% down and make sure it has at least 10% easy equity. 

With vacation rentals (especially in upscale, high-revenue areas on the beach) amenities such as pools, lazy rivers, landscaped grounds, exercise areas, etc are key in attracting year-round visitors.

Specifics: cash, seeking 2/1 to 3/2 SFR or multiplex, flip or BRRRR-type, possibly turn-key if time becomes an issue.

Sourcing those properties though can be difficult. 

Which booking platform you choose is going to depend on your area and some other key factors but in general, you will likely just need Airbnb & HomeAway/VRBO.