Helen, I love that book, its Maureen Peters isn't it. She wrote some good historical novels- "Anne the Rose of Hever" and A really lovely one about Mary-Rose, hope you can get your hands on them.
I think there possibly was some kind of romance (as far as Elizabeth was concerned anyway).
There are 3 contemporary sources that report that Richard was considering a match;
The Clerkenwell Declaration
In Spring of 1485, Richard publically and vehemently denied allegations of poisoning (of Queen Anne), of remarriage and his selection of Princess Elizabeth as wife, allegations that were in general circulation.
The marriage is also discussed in the Crowland Chronicle.
Probably most fascinating of all is a letter reportedly written in Elizabeth's own hand. If the letter is genuine, (and it is no longer extant), then Elizabeth consented to the marriage enthusiastically. In February 1485, Elizabeth of York wrote to the Duke of Norfolk expressing the hope that Queen Anne's illness would soon prove fatal and she would then marry her uncle King Richard. She fulsomely describes Richard as "her only joy and maker in this world" and that she was "his in heart, and in thoughts, in (body) and in all". (source= Buck). So, evidently she fancied the man as well as the crown he could bring her.
Politically, the marriage would have been advantageous. Also, Elizabeth was nubile,healthy, attractive-resembling her Aunt, the Queen in height, build and colouring.She could be expected to provide heirs speedily. The number of impediments to the marriage is also impressive, not least that marriage between Uncle and Niece constituted a blood relationship that was normally regarded as incestuous and Elizabeth was also closely related to Anne and Richard through other lines as well.