My custodian does not have a money market or similar sweep account to keep idle cash earning.

Welcome to the real estate hive.. are you open to exploring off-market listings through your network? 

Analyze Rental Comps & Market Trends•Look at recent rental comps in the community—not just those from a year ago, but the most recent listings with similar size, layout, and features.

They work well in areas with steady rental demand like suburban neighborhoods or cities with strong job markets​​.Considerations: Your property management needs will be lower, but rents may rise more slowly over time compared to short-term options.Short-Term Rentals: High Risk, High RewardAdvantages: Short-term rentals can generate significantly higher nightly rates, especially in vacation destinations.

Spring may be better but I was unable to sell a cheap house in October for 5% off of “market value” and only sold a $600k home in January by listing it for $580k and I still only got one offer. ($150k down, 5 year seller financing.) my point being you may get $20-$40k more in a year if you don’t need to sell. 

If you get greedy and put #3 in front of #1 or #2 you can get burned like any other market. 

For your seller its an effective sales price of ask - 2% using your assumed $500,000 thats $490,000, a real good offer depending on your market.  

It sounds like a single family house where you will be living in the house(personal use).Therefore, you may not be getting the tax benefits you think you are.Consult an accountant.I am not sure why your sister would agree to this as well, she is losing $170,000 in this transaction and she faces the possibility of you increasing her rent.You also have to charge market rent or close to market rent or it is all deemed personal use.

In the future I would like to run Facebook and instagram ads in a market that guest from.

I’m active in the market and happy to share insights on neighborhoods, financing options, or connect you with resources.