Edit. Oh .. I also invested just before the dot com crash. I looked at the historical charts and can't believe my timing.
But anyway it is a reasonably sound plan for what you are doing.
You need short-term bond (6-month, 1-month or even shorter) so that at worst you will get 100% of your money out by waiting for the maturity date. Money-market would be super short term: consider them as days-length bond.
But if we are talking about down payment money here, it's probably 100-200k something, which would translate to a few thousand dollars per year. Might not be worth your time, and definitely not worth it if you misunderstand and buy ETF bond or something like that. So yeah, keep it in a high-interest rate saving account is ok.