When Mrs Topham, who owned Aintree, was struggling financially in the late 60s and Airntee was starting to look a bit of a dump in need of a refurb. There were plans for bith teams to build a joint stadium.I remember being told that EFC (and I think the other lot) were looking at a site on the docks and this must have been 30 years ago. How seriously they looked into it is anybody's guess. I'm pretty sure it was even pre Peter Johnson.
iirc, John Moore's was neutral, but not against.
Prices. The then New Main Stand cost £770,000 and Mrs Topham was looking for £4.5M for the whole massive site.
Again, iirc, the plan was for the new joint stadium to back in to the new main race track stand or some such.