G’day fxxxrr,
Some stories about the EH and the camper for the seat sounds like an excellent swap!

I’m trying to imagine an EH ambulance getting down the highway with a teardrop camper in tow! What a brilliant sight that would be.
The pedal thing should be very fixable. A couple of thoughts.
If the pedal has too much travel then the corks may need replacing and/or the pulley bearings.
If the problem is just the at rest position of the pedal then a few things could contributing:
The transmission pulley stack needs to be centred with reference to the transmission drive fork pivot. In one of your photos is looks like it may not be centred - but it’s had to tell in the photo. The whole assembly (including the shaft) can be slid on the mount bearings and is then locked in place with collars similar to the ones that hold the wheels on your dads machine- assuming it’s the same as my later machine. In fact if these collars aren’t locked tight the shaft might be sliding in the bearings and this would increase the pedal travel.
The rod from the pedal to the drive fork link is adjustable. Lengthen or shorten to alter the pedal position.
I noticed in one of the photos that you took of the springs that this rod on your machine has a significant bend in it. The older machines don’t have this bend and I’m guessing (?) it shouldn’t be there. If it were straightened this will alter the pedal position heaps?
Hope this helps.
Cheers,