Creative Financing Help

[Guido Bertoli]

My Mom wants to sell her house.  She lives in the Bay Area in California and her house is worth approx $900,000. She will be moving to another state and be paying approx $600,000 for a house.

My idea is to get a loan for 600k and take over her mortgage, repairs, taxes, etc. Her current mortgage is about 3k. So I would essentially be renting her house and cover all repairs needed and then was going to sub lease it out and collect the difference. I can probably get 4k per month in rent. My moms concern is how does she get the additional 300k? I can sell her on the idea of getting the 300k later, but obviously you don't know where the market will be in 6 months or 5 years.

Any advice on how to handle this?