New owners and questions on upgrades

Hi Folks,

We have been enjoying our 2019 T@B 320 S so far. We have had some questions on upgrades and wondered if you guys have ever done any of these with success?

1. Cushions seems way to hard for comfort. For sleeping we have tried a 2 inch memory foam topper, helped a little but still very hard to sleep comfortably. The same is true with just sitting and watching TV, butt get sore after 30 minutes or so. I know comfort is pretty subjective but I was thinking if I bought a memory foam mattress that was the same thickness of the cushions I could cut it the same size as the cushions and zip off the covers and replace the foam inside?

2. Outside AC cover? I have seen the diamond plate AC cover, not really my style though. Is there any other options for a plain looking cover for the outside AC vent? 

3. Can we easily upgrade the TV in the camper to one slightly bigger? It would be nice to have one with more HDMI inputs and 1080p, Not sure if this TV uses just a standard bracket and wiring? I'm guessing the power is going to be a challenge as most TV use that standard black plug for power.

4. Alde 3020 Hot water, We tried the shower and found that the hot water moved around alot from barely warm to pretty warm. (Every 5-10 seconds or so) never really stayed consistent. We adjusted the mixing valve to various settings and the water certainly gets hotter, but never seems to stay around one temperature even right at the beginning of a shower. I read about possibly needing to reset the air cushion in the chamber, maybe that has something to do with it?

Thanks!