Lands End is a dump, parking is pricy and it'll be very very busy. Don't pay for the "experiences", it's absolutely not worth it.
However, if you drive out to Sennen, park down near the beach and walk the costal path round the cliffs and you can get into LE that way. That's not busy and you still get to see things.
Would recommend looking at what's on at The Minack Theatre, it's amazing.
Head out to St Just, have a potter about and lunch in The Star Inn. Lots of nice places around there to drive to for the day.
Lamorna Cove is lovely. Pop up to the Merry Maidens stone circle. There's also Carn Runy - prehistoric ruins of a village - which isn't far away. Or go up to Chysauster.
St Michael's Mount - walk over from Pz and avoid the crazy car parking. Walk to the Mount, but check tide times and whether the village is open or if you need a ticket to access it. It'll be busy but lots of space on Marazion and Long Rock beaches.
There's the butterfly house at St Hillary. Paradise Park in Hayle. The Seal Sanctuary at Gweek.
Trevaskis Farm at Hayle for the insane cakes.
Coverack is a bit of a drive but it's a pretty little place.