Her significant other bought their residence while she bought an Airbnb (very successful!)

@Clint Miller, this is very dependent on each situation.  

It's very simple.

Hi @Adam HoekerI have my clients all on QuickBooks Online.We sync in their accounts to reduce human error in entries, and track each property's expenses and transactions to prepare for Tax time, this helps us to be prepared for 1099s as well, track Asset Basis and Depreciation, Mortgage Balances, and any Equity items.Since QBO is very common, it is easy to connect a Tax Accountant to this as well and have them pop in to grab reports they need to file. 

imho, that was very overkill. 

If you use credit cards, I recommend having a designated credit card that you solely use for the rental property as well.This will keep your transactions for the property very organized and easy to find for tax season assuming you don't already have bookkeeping set up.

For properties that size I'm not sure cap rates will give the best story, but for the sake of answering the question, cap rates are a level of desirability in that sub market. 

starting by just brokering loans is a good way to start in states that do not require a license.. raising capital from private investors to make loans is a long process And very difficult if you do not have a long track record or pedigree in the industry.. if someone is brand new they really need to go work for a lender first.. other wise IMHO the chance of success is very small.

looking for suggestions on best methods/websites for marketing a long term rental.

Best of Luck!