hi Gary
answer to 1 you can carry a rifle in a slip as long as its secure if its not then yes you can be arrested
answer to 2 it is always best to have written permission what ever land your shooting on
answer to 3 i always call the police for a U.R.N. number to log my shooting activity my personal opinion
{ reason i don't want the ARU on my ass again }
answer to 4 trespassing with a firearm YES
Hope this helps
regards
Davy