Dear Professor D.N. Jha,
I cannot answer to  all your queries, but you may find useful the short article I have written a few years ago on the issue of "travel regulations" for the Brill Encyclopaedia of Hinduism, as it contains some bibliographical references. I have also written (in French) a long article on the difficulties raised by the journey to England of the maharaja of Jaipur in 1902 (to attend the coronation of Edward VII) (see:  http://ceias.ehess.fr/docannexe/file/2942/rester_hindou_en_mer_pour_le_site_du_ceias_mars_2014.pdf).Besides,  I have  published a paper on the equation of sea-travel with a "sin" (Clementin-Ojha, Catherine,  “Sin and expiation among modern Hindus: obeying one’s duty or following freely accepted rules?” in Sins and Sinners. Perspectives from Asia Religions edited by Phyllis Granoff and Koichi Shinohara, Leiden, Brill, 2012, pp. 357-380).

I'll be happy to correspond with you on this subject,
Best wishes,
Catherine Clémentin-Ojha