Hesitant to start a buy-and-hold with 3 kids entering college

[Frank Perkins]

I have 3 kids entering college in 2025, 2028, and 2032.  I'd like to have the option to send them to private high school prior as well if we think it's the best option (2021, 2024, 2028).

I'm extremely attracted to the buy-and-hold investment strategy, but I'm concerned about lack of liquidity in the 2020s. 

If I tie up all my capital in real estate, and I find myself needing $120K in tuition in just one year (2028 will have 2 overlapping, potentially 3 if private high school), then I may be regretting pursuing real estate.

Am I thinking about this the right way?  Would appreciate any input.  Thanks.