Is it acceptable to have a figure caption running to the next page? I have a large figure with a long caption of 300 words, and they really don't fit into one A4 page. Can I enlarge the figure to fit in the first page and let the caption run to the next page?
300 words will be about 30-50% of the page. Such a large chunk of text seems substantial, so it's better to place it in the body of the paper.

In such situations, in the caption I usually just state what's in the figure, followed by "see text for details". And then I don't care if the text spills to another page.