Smooth vertical page scrolling using mouse wheel and scroll bar

Try this one. https://nicescroll.areaaperta.com/

It has got

$().scrollTop() 

jQuery event listener too so you can have scroll path configured with parallax script.

I think you have to combine several of these effects in order to make something that resembles the Landrover site. A Smooth scroll script, a scroll path script and a parallax script.

This is an interesting site for the path element of that website: http://joelb.me/scrollpath/

Though the best way to find out how these sites work is to examine them! Some cool sites useing parallax: http://www.awwwards.com/?s=parallax&post_type=all&search=Ok

I hope this was of some help/inspiration!