Sorry about the loss of your dog, Mandy. They become a big part of the family. Maybe the sound reduction, as you said, will help with calm Marta.
Our Lab, Lucy, sits between us on 2 crates and bedding (so she can see out better) practically the whole time we're traveling in the RV and loves it. Gets excited over seeing cows and horses.
Of course she loves travelling in any vehicle anytime.
Good luck with the future mods.