Raldl...I am very familiar with your complaint.
MY set-up is very similar to yours: '08 Tundra DC 4X4,off-road pkg. with Bilsteins and Airlift 5000 airbags, 2011 Keystone Outback 250RS @ 6,000 dry, 1K/10K Equalizer.
I had the Airlift's installed a couple years ago in part to hopefully help calm-down the "porpoising" on some of the Iowa and Wisconsin concrete roads we frequently travel...it helped some but nowhere near enough, and the Janesville I90 and south-Madison bypass just made us sick. What I found helped was INCREASED speed...running 70-75, but I hated watching the gas suck and worried about the hefty fines if I got caught.
What has truly nearly eliminated the jounce was PROPERLY adjusting my Equalizer. Before our last trip I spent 3 hours out front of the house on the level street with the set-up, wrenches, levels and measure tapes. I carefully watched the Equalizer video and read and re-read the instructions, and had a copy of them with me in the street. I discovered I didn't have enough washers tilting the hitch head to distribute more weight to the truck front axle. Once I got the set-up correct, and the drop when hooking-up pretty equalized between the front and rear wheel-well arches....WOW, all the difference in the world!!!!
We drove some of our usual "make me sick" roads in northern Iowa and southern Wisconsin for our last trip...very, very comfortable at last! And I don't use the Airlifts nearly at all with the bars now.
If you have any questions, PM me.
Regards, BGood