The Samsung RF18 at 24.5" width with doors removed should fit through your Bounder 35E door opening that's slightly larger than 24.5". However, precise measurement and careful planning are essential for successful installation.
E-450 captain chair armrests usually not factory adjustable. Options include seat cushion to raise yourself, modifying mounting brackets, or aftermarket replacement seats with adjustable armrests.
Weak factory RV refrigerator latches can be easily upgraded with stronger aftermarket options like positive-latch catches, magnetic latches, or adjustable door strikes. Most solutions are DIY-friendly and cost under $30.
Thor Avanti renovation is very doable. Jackknife sofa can replace dinette, vinyl plank flooring is popular, and mattress can be replaced with standard size in most cases.
Flaking faux leather is common on RV seats and typically not covered by warranty on older units. Options are seat covers (most affordable), professional reupholstery (500-1500 per seat), or replacement seats. UV and heat cause material breakdown.
Replace failing N3150 with NovaKool R4500 compressor for better heat performance or Norcold N3141 for absorption drop-in. NovaKool better for boondocking with solar, absorption for propane versatility.