thats easy, jump into the ditch from towards where off the walls is, with special meter full, then manual, hit the qp, revert manual and then spacewalk up the ditch. alternatively, spine into it from where the hotel is, then manual with a spacewalk, turn around, and go down again.
as for going over the helicopter, go up the qp opposite the ramp, after the 2 pipes. make sure to get special. now, land, and then grind the edge of the hotel directly leading to the ramp you have to take to go over the heli. the grind should give you speed. ollie off the end, then do your mctwist. it helps top make it a button combo you can pull each time. make sure to jump right at the end of the ramp; not before. or do a bneless, in which case you need to jam the buttons for the mctwist really quickly..
that should do it.
*NS Skateboarders* Vas y il l'a cassé!
the previous might have been pure genious, but it wasn't my intention. sorry. that's why i put in all those typos...