But, excel is totally fine in the beginning.We use QuickBooks Online exclusively for all of our REI Clients.

I use QuickBooks Online for rentals and most of my clients.

Alternatively, you can check that one, it's also free to use:https://www.realestatespreadsheets.com/online-airbnb-estimat... 

Quote from @Shiv Panda: You can buy them online, maybe even at large box stores like Home Depot, Lowes, or other appliance retailers.I did a search for "commercial washer dryer card operated" and came up with many sites that sell them.

To find your first deal, use online forums, networking, wholesaling strategies, and online platforms.

They want more online leads, but I'm quickly learning their bigger issue is outbound sales & marketing, i.e. understanding who their customers (and referral partners) are and engaging them meaningfully.I've been lurking on BP and researching their build areas and it seems like their primary clients are developers and investors, not individuals building their dream vacation home (though they are part of the mix).Their value prop is dollar efficiency and speed.

Are there specific networking events, online platforms, or strategies that have proven effective for building relationships with investors?

Full accounting built-in with QuickBooks Online Sync if needed.

Listen to podcasts, watch YouTube videos, find others in similar boat and meet regularly online to discuss. 

Talk to a lender or read some online material to learn how to do it quickly and wisely.