I have the thule rapid load bars i think is what they are called along with the wind screen attachment on the front. They are strung across the factory rails and seem to do great, no loss in fuel economy. I only have loaded snowboards so far, havent tried the bike yet.

As far as the hauler goes the axles are slightly behind a regular camper but not much. Toy haulers generally have a higher dry tongue weight so that once the toys are loaded it balances everything out using the axles as a fulcrum to a certain extent. My triumph only weighs about 470lbs full of fuel and the tie downs center its mass right over the rear tire of the tandem axle. I hadnt really played around with it much but the fuel station tank is on the very rear of the trailer under the beaver tail loading area. And thats 30 gallons of fuel i can use as a counter weight to help with the tongue weight if it gets to heavy up front. The dry weight of this haulers tongue was 660lbs and with my bike and a half a tank on the rear I figured i was about right and it towed great except for the wind drag.

I ran the tire pressure a little higher incase the load on the rear tires got to high and at lower pressures thats what creates heat and blow outs. Slightly higher all around to also help with rolling resistance for fuel economy. Back down to normal now though.