More power for my Ford E450 32 Foot Forest River Sunseeker

1) Banks PowerPack
2) AFE intake (the K&N full intake looks close, but only replacing the filter element doesn't doesn't do much)
3) 5-star programmer

If your old rig was on an E350, that means your new rig probably weighs at least 3,000 pounds more, so slower should be expected. I do think the stock 4.56 gears should serve you well enough, but there is more power left behind in the motor.