You could play the Paladin as the main and have the Hunter on follow with a /assist+attack hotkey, the only issue you may run into is your ranged weapon will be to close too fire every time you engage a mob (you would just have to walk the Hunter back a few paces before firing).
An alternative would be to play your Hunter as main with the Pally following you. You could make three hotkeys for the Pally:
- one that targets the pet then heals
- one that targets the Hunter then heals
- one that assists the Hunter then casts Holy Shock (a little more DPS, or you could melee with 'interact with target')

either way it will be easy leveling, and you would have to fall asleep to get killed.