I have a 94 RoadTrek built on a 93 Chevy G30 chassie, I thought I had a problem with A/C and found that, that the unit was just a small window home unit which had no problems. ....But, since nothing was wrong with it, I found that it could be removed through the cabinet compartment over the Dinette. .....As for the safety belts I found a Company named Wesco Performance ....https://www.wescoperformance.com
Luck. oops! .......I almost forgot, I did replace my Radio and added a back-up camera, thats the easiest of all. ...I bought a Jensen that was just and easy swap Jensen is made by Aduiovox do a google search and you'll find them.