Listen to several people's replies before doing anything. Here are my comments, FWIW. I own an unrestored YM240 but it has a loader on the front, so it's not exactly comparable.
I expect the tractor with mowers is worth around $3,000 but for a rig this old, the price depends on condition. If it looks garage-kept and very respectable then more than $3,000. If weathered or even shabby, of course less, down to maybe $1800 for 'it simply runs'.
That
chipper is worth something, maybe $1,000? Anybody else know?
My suggestion is to put everything on Craigslist, local and additionally in any major metro area within 200 miles. Start at $4,000 for everything, or more if you think it shows good 'curb appeal'. Maybe try $5,000 if it really looks excellent. These are classics and somebody will pay good money for one that has the same appeal that they did new.
(Beware the Craigslist scammers! Safest is demand cash handed over inside the lobby of your own bank.) As a minimum phone the buyer back to verify his real phone plus write his driver's license # and license plate when you take his 'certified check' that could well be bogus).
I have the original YM240 sales brochures online and available via my sig at the bottom of this post. You might like to copy photos or quote specifications from that. If you have the service manuals or even the original receipt be sure to mention them in a Craigslist ad.
Now ... wait for some more replies and consider them before taking my opinion seriously. I obviously don't know your local market.
Also if you don't see many replies here, flag your own post (red triangle) and ask a moderator to move it to the Yanmar forum where all the enthusiasts hang out. Out here in the General forum many readers might get as far as '1979' and quit reading.