I finished raising our dinette seat. I added 5 1/2" in height. This is the height using 1x6 lumber. This may be too high but it's a lot easier to cut an inch or two off than add. So I'm starting with 5 1/2". The framework is pretty simple, just boxed in with 1x6. I cut new 1x2 side pieces to raise the center support.
I just used screws to hold the box together.
Then held it in place with pocket screws to the existing framing. The front outside corner isn't solid and Escape depended on the plywood seat to hold it together. In that corner I added two angle brackets to take some more load.
I used the original plywood seat base. It fit well although there is 3/4" or so gap at the front. I used the screws ETI did to hold the plywood to the new framing. It opens as before.
Finally I did the same to the street side.
As I mentioned the 5 1/2" is likely too high. We'll use this for some time and if needed cut some height off. This will be fairly easy and I planned for it during construction. It'll take a couple of longer trips to test it out. We won't put in a raised floor yet either. With 5 1/2" higher dinette a higher floor is likely worthwhile. But we'll try it without first.
When we decide on the height, I'll come back and put 1/8" oak plywood and oak trim on to finish up the look. Either just add from the existing panelling up or replace the dinette faces. This will probably depend on whether the floor is raised or not. If the power panel is raised it'll require new faces.