Sounds like a fun encounter.
For monsters, as he suggests, you can just roll the whole lot into a power.
Very rough example:
"THE JUNGLE...IT CAME ALIVE AND TOOK HIM" (Standard Action, Recharge 4+)
Melee 1 (one creature)
Str vs. AC
Hit: X damage (lots!), and make a secondary attack against the same target
Secondary Attack: Str vs. Fortitude
Hit: The ape grabs the target and shifts up to 5 squares, pulling the target with it. The ape can use this power to climb with the target.
Effect: The ape can shift up to 5 squares before making the primary attack
Here, the shift before the attack can be used to represent the jump. Neither shifting nor forced movement provoke opportunity attacks.