We also just generally have a fair amount of tourism and Bachelor/Bachelorette parties.

I prefer locations near DC, MD, VA, NJ, or NY, with year-round or seasonal tourism.

Are there tourism statistics out there that would help me determine if this investment would pay off?

You want places that have a long track record of tourism that depend on that vacation rental money. 

STRs (tourism, whether from out of state residents or locals)4.

Grand Haven city ordinances are very strict on where short-term rentals are permitted due to tourism being such a big part of its economy.

San Antonio is driven by tourism, military and healthcare sectors.

Do you like going to the theme parks or the shopping/dining that is here due to all the tourism, or just a clean, friendly city?

Truly motivated sellers aren't going to care as long as you provide the solution to their problem (and you typically get more motivated sellers from inbound marketing like Google Ads than outbound marketing like cold calling).But one thing you can do is explain the wholesale fee by comparing it to what they are saving (agent commissions, various closing costs/fees if you cover those, etc.). 

The off-season in these areas usually falls outside the summer months when beach tourism is at its peak.