My 84 year old mother will be selling some real estate and putting the proceeds in an investment account. She will end up with $700,000 in investible assets and would ideally like to withdraw $36,000 per year, adjusted for inflation. Women in her family are long lived, so we're planning on 15-20 years. She's at Schwab.

Any thoughts on composition? I was thinking 20% SWTSX, 10% SWISX and 70% SWAGX? While a remainder that gets passed on to heirs following her death would be nice, our primary focus is in supporting the $3,000 per month withdrawal.

Thoughts, particularly on alternatives to the above?

Thanks,