“if they get the 600 I am selling”
Make sure your sale is contingent on your finding and locking in a suitable replacement.
I got a motorhome... you got 600K, house is yours. clearing 400K will buy me a nice home in a red state. I’ll figure it out.
you want the snow blower too? it’s yours
Generator for when the grid goes down (it does) yours too
Lawn mower? well.. why not. it needs some maintenance anyways.
400K after 6 years in profit, you run with that money before they change their minds.