Welcome to UKCS.
Two questions there. Can’t specifically answer either but I’d suggest you go to a MH dealer that can look up the template for where to drill the holes. If the holes go in the wrong place, you could get water ingress at the back. The template may be available online, but I can’t be sure.
You don’t by any chance have a towbar fitted to your MH? If you do then you could fit a bike rack to it.
------------- XVI yes?
As well is two words!
How does a sage know everything about everything? or does he? or does he just think he does?
Remember, if you buy something you bought it, not brought it.