I have never seen an appointment diary, and doubt that there would be one.

Nor a list of the books he took with him, only the Prayer Book in Spanish given to him by the Ladies of Llangollen.

Have you seen the material in lifeofwellington.co.uk ? That's where I have put much of the extra detail that I couldn't fit into my biography of Wellington, and between that and the book I've done what I can to trace Wellington's movements, plans and activities between leaving London and landing in Portugal; but there are gaps in the surviving evidence.