Try leveling out the ride by increasing the air in the rear suspension and see if that makes a difference. If it does, keep increasing it until it gets either to the max or where it make the front handling where you like.
Same advice here,i usually run mine at 32-33 with 2 up,but with a heavier lady have had it up to 40-42. Also,i run 2 to 3 psi in the front at all times.Also,make sure you do the adjustment with both of you on the bike.She will probably notice a better ride as well after you increase it. '94 1500 SE
another thought, I have known a couple of people that got the voyager kit, and found it wanting. Since it doesn 't really help support the rear, it may not solve your problem if rear shock pressure doesn't help. Will help keep you up at stops though.
Also, check tire pressure! With a passenger, you may want to add 2 to 5 extra psi (cold, don't exceed max levels!) if you are running stock pressures.
Good luck, and if you really need a trike, consider converting your bike, or trading for a real trike.